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![Elijah Newren](/assets/img/avatar_default.png)
Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1619 lines
44 KiB
C
1619 lines
44 KiB
C
#include "../git-compat-util.h"
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#include "../alloc.h"
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#include "../config.h"
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#include "../hex.h"
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#include "../refs.h"
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#include "refs-internal.h"
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#include "packed-backend.h"
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#include "../iterator.h"
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#include "../lockfile.h"
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#include "../chdir-notify.h"
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enum mmap_strategy {
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/*
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* Don't use mmap() at all for reading `packed-refs`.
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*/
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MMAP_NONE,
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/*
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* Can use mmap() for reading `packed-refs`, but the file must
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* not remain mmapped. This is the usual option on Windows,
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* where you cannot rename a new version of a file onto a file
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* that is currently mmapped.
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*/
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MMAP_TEMPORARY,
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/*
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* It is OK to leave the `packed-refs` file mmapped while
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* arbitrary other code is running.
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*/
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MMAP_OK
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};
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#if defined(NO_MMAP)
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static enum mmap_strategy mmap_strategy = MMAP_NONE;
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#elif defined(MMAP_PREVENTS_DELETE)
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static enum mmap_strategy mmap_strategy = MMAP_TEMPORARY;
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#else
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static enum mmap_strategy mmap_strategy = MMAP_OK;
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#endif
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struct packed_ref_store;
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/*
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* A `snapshot` represents one snapshot of a `packed-refs` file.
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*
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* Normally, this will be a mmapped view of the contents of the
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* `packed-refs` file at the time the snapshot was created. However,
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* if the `packed-refs` file was not sorted, this might point at heap
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* memory holding the contents of the `packed-refs` file with its
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* records sorted by refname.
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*
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* `snapshot` instances are reference counted (via
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* `acquire_snapshot()` and `release_snapshot()`). This is to prevent
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* an instance from disappearing while an iterator is still iterating
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* over it. Instances are garbage collected when their `referrers`
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* count goes to zero.
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*
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* The most recent `snapshot`, if available, is referenced by the
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* `packed_ref_store`. Its freshness is checked whenever
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* `get_snapshot()` is called; if the existing snapshot is obsolete, a
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* new snapshot is taken.
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*/
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struct snapshot {
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/*
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* A back-pointer to the packed_ref_store with which this
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* snapshot is associated:
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*/
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struct packed_ref_store *refs;
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/* Is the `packed-refs` file currently mmapped? */
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int mmapped;
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/*
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* The contents of the `packed-refs` file:
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*
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* - buf -- a pointer to the start of the memory
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* - start -- a pointer to the first byte of actual references
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* (i.e., after the header line, if one is present)
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* - eof -- a pointer just past the end of the reference
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* contents
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*
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* If the `packed-refs` file was already sorted, `buf` points
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* at the mmapped contents of the file. If not, it points at
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* heap-allocated memory containing the contents, sorted. If
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* there were no contents (e.g., because the file didn't
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* exist), `buf`, `start`, and `eof` are all NULL.
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*/
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char *buf, *start, *eof;
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/*
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* What is the peeled state of the `packed-refs` file that
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* this snapshot represents? (This is usually determined from
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* the file's header.)
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*/
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enum { PEELED_NONE, PEELED_TAGS, PEELED_FULLY } peeled;
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/*
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* Count of references to this instance, including the pointer
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* from `packed_ref_store::snapshot`, if any. The instance
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* will not be freed as long as the reference count is
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* nonzero.
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*/
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unsigned int referrers;
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/*
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* The metadata of the `packed-refs` file from which this
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* snapshot was created, used to tell if the file has been
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* replaced since we read it.
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*/
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struct stat_validity validity;
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};
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/*
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* A `ref_store` representing references stored in a `packed-refs`
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* file. It implements the `ref_store` interface, though it has some
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* limitations:
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*
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* - It cannot store symbolic references.
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*
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* - It cannot store reflogs.
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*
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* - It does not support reference renaming (though it could).
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*
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* On the other hand, it can be locked outside of a reference
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* transaction. In that case, it remains locked even after the
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* transaction is done and the new `packed-refs` file is activated.
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*/
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struct packed_ref_store {
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struct ref_store base;
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unsigned int store_flags;
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/* The path of the "packed-refs" file: */
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char *path;
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/*
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* A snapshot of the values read from the `packed-refs` file,
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* if it might still be current; otherwise, NULL.
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*/
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struct snapshot *snapshot;
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/*
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* Lock used for the "packed-refs" file. Note that this (and
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* thus the enclosing `packed_ref_store`) must not be freed.
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*/
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struct lock_file lock;
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/*
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* Temporary file used when rewriting new contents to the
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* "packed-refs" file. Note that this (and thus the enclosing
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* `packed_ref_store`) must not be freed.
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*/
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struct tempfile *tempfile;
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};
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/*
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* Increment the reference count of `*snapshot`.
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*/
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static void acquire_snapshot(struct snapshot *snapshot)
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{
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snapshot->referrers++;
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}
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/*
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* If the buffer in `snapshot` is active, then either munmap the
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* memory and close the file, or free the memory. Then set the buffer
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* pointers to NULL.
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*/
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static void clear_snapshot_buffer(struct snapshot *snapshot)
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{
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if (snapshot->mmapped) {
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if (munmap(snapshot->buf, snapshot->eof - snapshot->buf))
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die_errno("error ummapping packed-refs file %s",
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snapshot->refs->path);
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snapshot->mmapped = 0;
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} else {
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free(snapshot->buf);
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}
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snapshot->buf = snapshot->start = snapshot->eof = NULL;
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}
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/*
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* Decrease the reference count of `*snapshot`. If it goes to zero,
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* free `*snapshot` and return true; otherwise return false.
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*/
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static int release_snapshot(struct snapshot *snapshot)
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{
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if (!--snapshot->referrers) {
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stat_validity_clear(&snapshot->validity);
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clear_snapshot_buffer(snapshot);
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free(snapshot);
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return 1;
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} else {
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return 0;
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}
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}
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struct ref_store *packed_ref_store_create(struct repository *repo,
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const char *gitdir,
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unsigned int store_flags)
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{
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struct packed_ref_store *refs = xcalloc(1, sizeof(*refs));
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struct ref_store *ref_store = (struct ref_store *)refs;
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struct strbuf sb = STRBUF_INIT;
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base_ref_store_init(ref_store, repo, gitdir, &refs_be_packed);
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refs->store_flags = store_flags;
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strbuf_addf(&sb, "%s/packed-refs", gitdir);
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refs->path = strbuf_detach(&sb, NULL);
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chdir_notify_reparent("packed-refs", &refs->path);
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return ref_store;
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}
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/*
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* Downcast `ref_store` to `packed_ref_store`. Die if `ref_store` is
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* not a `packed_ref_store`. Also die if `packed_ref_store` doesn't
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* support at least the flags specified in `required_flags`. `caller`
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* is used in any necessary error messages.
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*/
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static struct packed_ref_store *packed_downcast(struct ref_store *ref_store,
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unsigned int required_flags,
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const char *caller)
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{
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struct packed_ref_store *refs;
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if (ref_store->be != &refs_be_packed)
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BUG("ref_store is type \"%s\" not \"packed\" in %s",
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ref_store->be->name, caller);
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refs = (struct packed_ref_store *)ref_store;
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if ((refs->store_flags & required_flags) != required_flags)
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BUG("unallowed operation (%s), requires %x, has %x\n",
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caller, required_flags, refs->store_flags);
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return refs;
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}
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static void clear_snapshot(struct packed_ref_store *refs)
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{
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if (refs->snapshot) {
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struct snapshot *snapshot = refs->snapshot;
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refs->snapshot = NULL;
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release_snapshot(snapshot);
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}
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}
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static NORETURN void die_unterminated_line(const char *path,
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const char *p, size_t len)
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{
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if (len < 80)
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die("unterminated line in %s: %.*s", path, (int)len, p);
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else
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die("unterminated line in %s: %.75s...", path, p);
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}
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static NORETURN void die_invalid_line(const char *path,
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const char *p, size_t len)
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{
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const char *eol = memchr(p, '\n', len);
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if (!eol)
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die_unterminated_line(path, p, len);
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else if (eol - p < 80)
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die("unexpected line in %s: %.*s", path, (int)(eol - p), p);
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else
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die("unexpected line in %s: %.75s...", path, p);
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}
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struct snapshot_record {
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const char *start;
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size_t len;
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};
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static int cmp_packed_ref_records(const void *v1, const void *v2)
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{
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const struct snapshot_record *e1 = v1, *e2 = v2;
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const char *r1 = e1->start + the_hash_algo->hexsz + 1;
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const char *r2 = e2->start + the_hash_algo->hexsz + 1;
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while (1) {
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if (*r1 == '\n')
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return *r2 == '\n' ? 0 : -1;
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if (*r1 != *r2) {
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if (*r2 == '\n')
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return 1;
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else
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return (unsigned char)*r1 < (unsigned char)*r2 ? -1 : +1;
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}
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r1++;
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r2++;
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}
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}
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/*
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* Compare a snapshot record at `rec` to the specified NUL-terminated
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* refname.
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*/
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static int cmp_record_to_refname(const char *rec, const char *refname)
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{
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const char *r1 = rec + the_hash_algo->hexsz + 1;
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const char *r2 = refname;
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while (1) {
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if (*r1 == '\n')
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return *r2 ? -1 : 0;
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if (!*r2)
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return 1;
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if (*r1 != *r2)
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return (unsigned char)*r1 < (unsigned char)*r2 ? -1 : +1;
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r1++;
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r2++;
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}
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}
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/*
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* `snapshot->buf` is not known to be sorted. Check whether it is, and
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* if not, sort it into new memory and munmap/free the old storage.
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*/
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static void sort_snapshot(struct snapshot *snapshot)
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{
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struct snapshot_record *records = NULL;
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size_t alloc = 0, nr = 0;
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int sorted = 1;
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const char *pos, *eof, *eol;
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size_t len, i;
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char *new_buffer, *dst;
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pos = snapshot->start;
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eof = snapshot->eof;
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if (pos == eof)
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return;
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len = eof - pos;
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/*
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* Initialize records based on a crude estimate of the number
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* of references in the file (we'll grow it below if needed):
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*/
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ALLOC_GROW(records, len / 80 + 20, alloc);
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while (pos < eof) {
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eol = memchr(pos, '\n', eof - pos);
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if (!eol)
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/* The safety check should prevent this. */
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BUG("unterminated line found in packed-refs");
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if (eol - pos < the_hash_algo->hexsz + 2)
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die_invalid_line(snapshot->refs->path,
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pos, eof - pos);
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eol++;
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if (eol < eof && *eol == '^') {
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/*
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* Keep any peeled line together with its
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* reference:
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*/
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const char *peeled_start = eol;
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eol = memchr(peeled_start, '\n', eof - peeled_start);
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if (!eol)
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/* The safety check should prevent this. */
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BUG("unterminated peeled line found in packed-refs");
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eol++;
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}
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ALLOC_GROW(records, nr + 1, alloc);
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records[nr].start = pos;
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records[nr].len = eol - pos;
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nr++;
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if (sorted &&
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nr > 1 &&
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cmp_packed_ref_records(&records[nr - 2],
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&records[nr - 1]) >= 0)
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sorted = 0;
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pos = eol;
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}
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if (sorted)
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goto cleanup;
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/* We need to sort the memory. First we sort the records array: */
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QSORT(records, nr, cmp_packed_ref_records);
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/*
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* Allocate a new chunk of memory, and copy the old memory to
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* the new in the order indicated by `records` (not bothering
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* with the header line):
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*/
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new_buffer = xmalloc(len);
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for (dst = new_buffer, i = 0; i < nr; i++) {
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memcpy(dst, records[i].start, records[i].len);
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dst += records[i].len;
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}
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/*
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* Now munmap the old buffer and use the sorted buffer in its
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* place:
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*/
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clear_snapshot_buffer(snapshot);
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snapshot->buf = snapshot->start = new_buffer;
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snapshot->eof = new_buffer + len;
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cleanup:
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free(records);
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}
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/*
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* Return a pointer to the start of the record that contains the
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* character `*p` (which must be within the buffer). If no other
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* record start is found, return `buf`.
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*/
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static const char *find_start_of_record(const char *buf, const char *p)
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{
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while (p > buf && (p[-1] != '\n' || p[0] == '^'))
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p--;
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return p;
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}
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/*
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* Return a pointer to the start of the record following the record
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* that contains `*p`. If none is found before `end`, return `end`.
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*/
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static const char *find_end_of_record(const char *p, const char *end)
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{
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while (++p < end && (p[-1] != '\n' || p[0] == '^'))
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;
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return p;
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}
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/*
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* We want to be able to compare mmapped reference records quickly,
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* without totally parsing them. We can do so because the records are
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* LF-terminated, and the refname should start exactly (GIT_SHA1_HEXSZ
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* + 1) bytes past the beginning of the record.
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*
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* But what if the `packed-refs` file contains garbage? We're willing
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* to tolerate not detecting the problem, as long as we don't produce
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* totally garbled output (we can't afford to check the integrity of
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* the whole file during every Git invocation). But we do want to be
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* sure that we never read past the end of the buffer in memory and
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* perform an illegal memory access.
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*
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* Guarantee that minimum level of safety by verifying that the last
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* record in the file is LF-terminated, and that it has at least
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* (GIT_SHA1_HEXSZ + 1) characters before the LF. Die if either of
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* these checks fails.
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*/
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static void verify_buffer_safe(struct snapshot *snapshot)
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{
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const char *start = snapshot->start;
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const char *eof = snapshot->eof;
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const char *last_line;
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if (start == eof)
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return;
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last_line = find_start_of_record(start, eof - 1);
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if (*(eof - 1) != '\n' || eof - last_line < the_hash_algo->hexsz + 2)
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die_invalid_line(snapshot->refs->path,
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last_line, eof - last_line);
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}
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#define SMALL_FILE_SIZE (32*1024)
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|
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/*
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* Depending on `mmap_strategy`, either mmap or read the contents of
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* the `packed-refs` file into the snapshot. Return 1 if the file
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* existed and was read, or 0 if the file was absent or empty. Die on
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* errors.
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*/
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static int load_contents(struct snapshot *snapshot)
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{
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int fd;
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struct stat st;
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size_t size;
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ssize_t bytes_read;
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fd = open(snapshot->refs->path, O_RDONLY);
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if (fd < 0) {
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if (errno == ENOENT) {
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/*
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* This is OK; it just means that no
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* "packed-refs" file has been written yet,
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* which is equivalent to it being empty,
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* which is its state when initialized with
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* zeros.
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*/
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return 0;
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} else {
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die_errno("couldn't read %s", snapshot->refs->path);
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}
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}
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stat_validity_update(&snapshot->validity, fd);
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if (fstat(fd, &st) < 0)
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die_errno("couldn't stat %s", snapshot->refs->path);
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size = xsize_t(st.st_size);
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if (!size) {
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close(fd);
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return 0;
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} else if (mmap_strategy == MMAP_NONE || size <= SMALL_FILE_SIZE) {
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snapshot->buf = xmalloc(size);
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bytes_read = read_in_full(fd, snapshot->buf, size);
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if (bytes_read < 0 || bytes_read != size)
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die_errno("couldn't read %s", snapshot->refs->path);
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snapshot->mmapped = 0;
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} else {
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snapshot->buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
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snapshot->mmapped = 1;
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}
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close(fd);
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snapshot->start = snapshot->buf;
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snapshot->eof = snapshot->buf + size;
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return 1;
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}
|
|
|
|
/*
|
|
* Find the place in `snapshot->buf` where the start of the record for
|
|
* `refname` starts. If `mustexist` is true and the reference doesn't
|
|
* exist, then return NULL. If `mustexist` is false and the reference
|
|
* doesn't exist, then return the point where that reference would be
|
|
* inserted, or `snapshot->eof` (which might be NULL) if it would be
|
|
* inserted at the end of the file. In the latter mode, `refname`
|
|
* doesn't have to be a proper reference name; for example, one could
|
|
* search for "refs/replace/" to find the start of any replace
|
|
* references.
|
|
*
|
|
* The record is sought using a binary search, so `snapshot->buf` must
|
|
* be sorted.
|
|
*/
|
|
static const char *find_reference_location(struct snapshot *snapshot,
|
|
const char *refname, int mustexist)
|
|
{
|
|
/*
|
|
* This is not *quite* a garden-variety binary search, because
|
|
* the data we're searching is made up of records, and we
|
|
* always need to find the beginning of a record to do a
|
|
* comparison. A "record" here is one line for the reference
|
|
* itself and zero or one peel lines that start with '^'. Our
|
|
* loop invariant is described in the next two comments.
|
|
*/
|
|
|
|
/*
|
|
* A pointer to the character at the start of a record whose
|
|
* preceding records all have reference names that come
|
|
* *before* `refname`.
|
|
*/
|
|
const char *lo = snapshot->start;
|
|
|
|
/*
|
|
* A pointer to a the first character of a record whose
|
|
* reference name comes *after* `refname`.
|
|
*/
|
|
const char *hi = snapshot->eof;
|
|
|
|
while (lo != hi) {
|
|
const char *mid, *rec;
|
|
int cmp;
|
|
|
|
mid = lo + (hi - lo) / 2;
|
|
rec = find_start_of_record(lo, mid);
|
|
cmp = cmp_record_to_refname(rec, refname);
|
|
if (cmp < 0) {
|
|
lo = find_end_of_record(mid, hi);
|
|
} else if (cmp > 0) {
|
|
hi = rec;
|
|
} else {
|
|
return rec;
|
|
}
|
|
}
|
|
|
|
if (mustexist)
|
|
return NULL;
|
|
else
|
|
return lo;
|
|
}
|
|
|
|
/*
|
|
* Create a newly-allocated `snapshot` of the `packed-refs` file in
|
|
* its current state and return it. The return value will already have
|
|
* its reference count incremented.
|
|
*
|
|
* A comment line of the form "# pack-refs with: " may contain zero or
|
|
* more traits. We interpret the traits as follows:
|
|
*
|
|
* Neither `peeled` nor `fully-peeled`:
|
|
*
|
|
* Probably no references are peeled. But if the file contains a
|
|
* peeled value for a reference, we will use it.
|
|
*
|
|
* `peeled`:
|
|
*
|
|
* References under "refs/tags/", if they *can* be peeled, *are*
|
|
* peeled in this file. References outside of "refs/tags/" are
|
|
* probably not peeled even if they could have been, but if we find
|
|
* a peeled value for such a reference we will use it.
|
|
*
|
|
* `fully-peeled`:
|
|
*
|
|
* All references in the file that can be peeled are peeled.
|
|
* Inversely (and this is more important), any references in the
|
|
* file for which no peeled value is recorded is not peelable. This
|
|
* trait should typically be written alongside "peeled" for
|
|
* compatibility with older clients, but we do not require it
|
|
* (i.e., "peeled" is a no-op if "fully-peeled" is set).
|
|
*
|
|
* `sorted`:
|
|
*
|
|
* The references in this file are known to be sorted by refname.
|
|
*/
|
|
static struct snapshot *create_snapshot(struct packed_ref_store *refs)
|
|
{
|
|
struct snapshot *snapshot = xcalloc(1, sizeof(*snapshot));
|
|
int sorted = 0;
|
|
|
|
snapshot->refs = refs;
|
|
acquire_snapshot(snapshot);
|
|
snapshot->peeled = PEELED_NONE;
|
|
|
|
if (!load_contents(snapshot))
|
|
return snapshot;
|
|
|
|
/* If the file has a header line, process it: */
|
|
if (snapshot->buf < snapshot->eof && *snapshot->buf == '#') {
|
|
char *tmp, *p, *eol;
|
|
struct string_list traits = STRING_LIST_INIT_NODUP;
|
|
|
|
eol = memchr(snapshot->buf, '\n',
|
|
snapshot->eof - snapshot->buf);
|
|
if (!eol)
|
|
die_unterminated_line(refs->path,
|
|
snapshot->buf,
|
|
snapshot->eof - snapshot->buf);
|
|
|
|
tmp = xmemdupz(snapshot->buf, eol - snapshot->buf);
|
|
|
|
if (!skip_prefix(tmp, "# pack-refs with:", (const char **)&p))
|
|
die_invalid_line(refs->path,
|
|
snapshot->buf,
|
|
snapshot->eof - snapshot->buf);
|
|
|
|
string_list_split_in_place(&traits, p, ' ', -1);
|
|
|
|
if (unsorted_string_list_has_string(&traits, "fully-peeled"))
|
|
snapshot->peeled = PEELED_FULLY;
|
|
else if (unsorted_string_list_has_string(&traits, "peeled"))
|
|
snapshot->peeled = PEELED_TAGS;
|
|
|
|
sorted = unsorted_string_list_has_string(&traits, "sorted");
|
|
|
|
/* perhaps other traits later as well */
|
|
|
|
/* The "+ 1" is for the LF character. */
|
|
snapshot->start = eol + 1;
|
|
|
|
string_list_clear(&traits, 0);
|
|
free(tmp);
|
|
}
|
|
|
|
verify_buffer_safe(snapshot);
|
|
|
|
if (!sorted) {
|
|
sort_snapshot(snapshot);
|
|
|
|
/*
|
|
* Reordering the records might have moved a short one
|
|
* to the end of the buffer, so verify the buffer's
|
|
* safety again:
|
|
*/
|
|
verify_buffer_safe(snapshot);
|
|
}
|
|
|
|
if (mmap_strategy != MMAP_OK && snapshot->mmapped) {
|
|
/*
|
|
* We don't want to leave the file mmapped, so we are
|
|
* forced to make a copy now:
|
|
*/
|
|
size_t size = snapshot->eof - snapshot->start;
|
|
char *buf_copy = xmalloc(size);
|
|
|
|
memcpy(buf_copy, snapshot->start, size);
|
|
clear_snapshot_buffer(snapshot);
|
|
snapshot->buf = snapshot->start = buf_copy;
|
|
snapshot->eof = buf_copy + size;
|
|
}
|
|
|
|
return snapshot;
|
|
}
|
|
|
|
/*
|
|
* Check that `refs->snapshot` (if present) still reflects the
|
|
* contents of the `packed-refs` file. If not, clear the snapshot.
|
|
*/
|
|
static void validate_snapshot(struct packed_ref_store *refs)
|
|
{
|
|
if (refs->snapshot &&
|
|
!stat_validity_check(&refs->snapshot->validity, refs->path))
|
|
clear_snapshot(refs);
|
|
}
|
|
|
|
/*
|
|
* Get the `snapshot` for the specified packed_ref_store, creating and
|
|
* populating it if it hasn't been read before or if the file has been
|
|
* changed (according to its `validity` field) since it was last read.
|
|
* On the other hand, if we hold the lock, then assume that the file
|
|
* hasn't been changed out from under us, so skip the extra `stat()`
|
|
* call in `stat_validity_check()`. This function does *not* increase
|
|
* the snapshot's reference count on behalf of the caller.
|
|
*/
|
|
static struct snapshot *get_snapshot(struct packed_ref_store *refs)
|
|
{
|
|
if (!is_lock_file_locked(&refs->lock))
|
|
validate_snapshot(refs);
|
|
|
|
if (!refs->snapshot)
|
|
refs->snapshot = create_snapshot(refs);
|
|
|
|
return refs->snapshot;
|
|
}
|
|
|
|
static int packed_read_raw_ref(struct ref_store *ref_store, const char *refname,
|
|
struct object_id *oid, struct strbuf *referent UNUSED,
|
|
unsigned int *type, int *failure_errno)
|
|
{
|
|
struct packed_ref_store *refs =
|
|
packed_downcast(ref_store, REF_STORE_READ, "read_raw_ref");
|
|
struct snapshot *snapshot = get_snapshot(refs);
|
|
const char *rec;
|
|
|
|
*type = 0;
|
|
|
|
rec = find_reference_location(snapshot, refname, 1);
|
|
|
|
if (!rec) {
|
|
/* refname is not a packed reference. */
|
|
*failure_errno = ENOENT;
|
|
return -1;
|
|
}
|
|
|
|
if (get_oid_hex(rec, oid))
|
|
die_invalid_line(refs->path, rec, snapshot->eof - rec);
|
|
|
|
*type = REF_ISPACKED;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This value is set in `base.flags` if the peeled value of the
|
|
* current reference is known. In that case, `peeled` contains the
|
|
* correct peeled value for the reference, which might be `null_oid`
|
|
* if the reference is not a tag or if it is broken.
|
|
*/
|
|
#define REF_KNOWS_PEELED 0x40
|
|
|
|
/*
|
|
* An iterator over a snapshot of a `packed-refs` file.
|
|
*/
|
|
struct packed_ref_iterator {
|
|
struct ref_iterator base;
|
|
|
|
struct snapshot *snapshot;
|
|
|
|
/* The current position in the snapshot's buffer: */
|
|
const char *pos;
|
|
|
|
/* The end of the part of the buffer that will be iterated over: */
|
|
const char *eof;
|
|
|
|
/* Scratch space for current values: */
|
|
struct object_id oid, peeled;
|
|
struct strbuf refname_buf;
|
|
|
|
struct repository *repo;
|
|
unsigned int flags;
|
|
};
|
|
|
|
/*
|
|
* Move the iterator to the next record in the snapshot, without
|
|
* respect for whether the record is actually required by the current
|
|
* iteration. Adjust the fields in `iter` and return `ITER_OK` or
|
|
* `ITER_DONE`. This function does not free the iterator in the case
|
|
* of `ITER_DONE`.
|
|
*/
|
|
static int next_record(struct packed_ref_iterator *iter)
|
|
{
|
|
const char *p = iter->pos, *eol;
|
|
|
|
strbuf_reset(&iter->refname_buf);
|
|
|
|
if (iter->pos == iter->eof)
|
|
return ITER_DONE;
|
|
|
|
iter->base.flags = REF_ISPACKED;
|
|
|
|
if (iter->eof - p < the_hash_algo->hexsz + 2 ||
|
|
parse_oid_hex(p, &iter->oid, &p) ||
|
|
!isspace(*p++))
|
|
die_invalid_line(iter->snapshot->refs->path,
|
|
iter->pos, iter->eof - iter->pos);
|
|
|
|
eol = memchr(p, '\n', iter->eof - p);
|
|
if (!eol)
|
|
die_unterminated_line(iter->snapshot->refs->path,
|
|
iter->pos, iter->eof - iter->pos);
|
|
|
|
strbuf_add(&iter->refname_buf, p, eol - p);
|
|
iter->base.refname = iter->refname_buf.buf;
|
|
|
|
if (check_refname_format(iter->base.refname, REFNAME_ALLOW_ONELEVEL)) {
|
|
if (!refname_is_safe(iter->base.refname))
|
|
die("packed refname is dangerous: %s",
|
|
iter->base.refname);
|
|
oidclr(&iter->oid);
|
|
iter->base.flags |= REF_BAD_NAME | REF_ISBROKEN;
|
|
}
|
|
if (iter->snapshot->peeled == PEELED_FULLY ||
|
|
(iter->snapshot->peeled == PEELED_TAGS &&
|
|
starts_with(iter->base.refname, "refs/tags/")))
|
|
iter->base.flags |= REF_KNOWS_PEELED;
|
|
|
|
iter->pos = eol + 1;
|
|
|
|
if (iter->pos < iter->eof && *iter->pos == '^') {
|
|
p = iter->pos + 1;
|
|
if (iter->eof - p < the_hash_algo->hexsz + 1 ||
|
|
parse_oid_hex(p, &iter->peeled, &p) ||
|
|
*p++ != '\n')
|
|
die_invalid_line(iter->snapshot->refs->path,
|
|
iter->pos, iter->eof - iter->pos);
|
|
iter->pos = p;
|
|
|
|
/*
|
|
* Regardless of what the file header said, we
|
|
* definitely know the value of *this* reference. But
|
|
* we suppress it if the reference is broken:
|
|
*/
|
|
if ((iter->base.flags & REF_ISBROKEN)) {
|
|
oidclr(&iter->peeled);
|
|
iter->base.flags &= ~REF_KNOWS_PEELED;
|
|
} else {
|
|
iter->base.flags |= REF_KNOWS_PEELED;
|
|
}
|
|
} else {
|
|
oidclr(&iter->peeled);
|
|
}
|
|
|
|
return ITER_OK;
|
|
}
|
|
|
|
static int packed_ref_iterator_advance(struct ref_iterator *ref_iterator)
|
|
{
|
|
struct packed_ref_iterator *iter =
|
|
(struct packed_ref_iterator *)ref_iterator;
|
|
int ok;
|
|
|
|
while ((ok = next_record(iter)) == ITER_OK) {
|
|
if (iter->flags & DO_FOR_EACH_PER_WORKTREE_ONLY &&
|
|
!is_per_worktree_ref(iter->base.refname))
|
|
continue;
|
|
|
|
if (!(iter->flags & DO_FOR_EACH_INCLUDE_BROKEN) &&
|
|
!ref_resolves_to_object(iter->base.refname, iter->repo,
|
|
&iter->oid, iter->flags))
|
|
continue;
|
|
|
|
return ITER_OK;
|
|
}
|
|
|
|
if (ref_iterator_abort(ref_iterator) != ITER_DONE)
|
|
ok = ITER_ERROR;
|
|
|
|
return ok;
|
|
}
|
|
|
|
static int packed_ref_iterator_peel(struct ref_iterator *ref_iterator,
|
|
struct object_id *peeled)
|
|
{
|
|
struct packed_ref_iterator *iter =
|
|
(struct packed_ref_iterator *)ref_iterator;
|
|
|
|
if (iter->repo != the_repository)
|
|
BUG("peeling for non-the_repository is not supported");
|
|
|
|
if ((iter->base.flags & REF_KNOWS_PEELED)) {
|
|
oidcpy(peeled, &iter->peeled);
|
|
return is_null_oid(&iter->peeled) ? -1 : 0;
|
|
} else if ((iter->base.flags & (REF_ISBROKEN | REF_ISSYMREF))) {
|
|
return -1;
|
|
} else {
|
|
return peel_object(&iter->oid, peeled) ? -1 : 0;
|
|
}
|
|
}
|
|
|
|
static int packed_ref_iterator_abort(struct ref_iterator *ref_iterator)
|
|
{
|
|
struct packed_ref_iterator *iter =
|
|
(struct packed_ref_iterator *)ref_iterator;
|
|
int ok = ITER_DONE;
|
|
|
|
strbuf_release(&iter->refname_buf);
|
|
release_snapshot(iter->snapshot);
|
|
base_ref_iterator_free(ref_iterator);
|
|
return ok;
|
|
}
|
|
|
|
static struct ref_iterator_vtable packed_ref_iterator_vtable = {
|
|
.advance = packed_ref_iterator_advance,
|
|
.peel = packed_ref_iterator_peel,
|
|
.abort = packed_ref_iterator_abort
|
|
};
|
|
|
|
static struct ref_iterator *packed_ref_iterator_begin(
|
|
struct ref_store *ref_store,
|
|
const char *prefix, unsigned int flags)
|
|
{
|
|
struct packed_ref_store *refs;
|
|
struct snapshot *snapshot;
|
|
const char *start;
|
|
struct packed_ref_iterator *iter;
|
|
struct ref_iterator *ref_iterator;
|
|
unsigned int required_flags = REF_STORE_READ;
|
|
|
|
if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN))
|
|
required_flags |= REF_STORE_ODB;
|
|
refs = packed_downcast(ref_store, required_flags, "ref_iterator_begin");
|
|
|
|
/*
|
|
* Note that `get_snapshot()` internally checks whether the
|
|
* snapshot is up to date with what is on disk, and re-reads
|
|
* it if not.
|
|
*/
|
|
snapshot = get_snapshot(refs);
|
|
|
|
if (prefix && *prefix)
|
|
start = find_reference_location(snapshot, prefix, 0);
|
|
else
|
|
start = snapshot->start;
|
|
|
|
if (start == snapshot->eof)
|
|
return empty_ref_iterator_begin();
|
|
|
|
CALLOC_ARRAY(iter, 1);
|
|
ref_iterator = &iter->base;
|
|
base_ref_iterator_init(ref_iterator, &packed_ref_iterator_vtable, 1);
|
|
|
|
iter->snapshot = snapshot;
|
|
acquire_snapshot(snapshot);
|
|
|
|
iter->pos = start;
|
|
iter->eof = snapshot->eof;
|
|
strbuf_init(&iter->refname_buf, 0);
|
|
|
|
iter->base.oid = &iter->oid;
|
|
|
|
iter->repo = ref_store->repo;
|
|
iter->flags = flags;
|
|
|
|
if (prefix && *prefix)
|
|
/* Stop iteration after we've gone *past* prefix: */
|
|
ref_iterator = prefix_ref_iterator_begin(ref_iterator, prefix, 0);
|
|
|
|
return ref_iterator;
|
|
}
|
|
|
|
/*
|
|
* Write an entry to the packed-refs file for the specified refname.
|
|
* If peeled is non-NULL, write it as the entry's peeled value. On
|
|
* error, return a nonzero value and leave errno set at the value left
|
|
* by the failing call to `fprintf()`.
|
|
*/
|
|
static int write_packed_entry(FILE *fh, const char *refname,
|
|
const struct object_id *oid,
|
|
const struct object_id *peeled)
|
|
{
|
|
if (fprintf(fh, "%s %s\n", oid_to_hex(oid), refname) < 0 ||
|
|
(peeled && fprintf(fh, "^%s\n", oid_to_hex(peeled)) < 0))
|
|
return -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int packed_refs_lock(struct ref_store *ref_store, int flags, struct strbuf *err)
|
|
{
|
|
struct packed_ref_store *refs =
|
|
packed_downcast(ref_store, REF_STORE_WRITE | REF_STORE_MAIN,
|
|
"packed_refs_lock");
|
|
static int timeout_configured = 0;
|
|
static int timeout_value = 1000;
|
|
|
|
if (!timeout_configured) {
|
|
git_config_get_int("core.packedrefstimeout", &timeout_value);
|
|
timeout_configured = 1;
|
|
}
|
|
|
|
/*
|
|
* Note that we close the lockfile immediately because we
|
|
* don't write new content to it, but rather to a separate
|
|
* tempfile.
|
|
*/
|
|
if (hold_lock_file_for_update_timeout(
|
|
&refs->lock,
|
|
refs->path,
|
|
flags, timeout_value) < 0) {
|
|
unable_to_lock_message(refs->path, errno, err);
|
|
return -1;
|
|
}
|
|
|
|
if (close_lock_file_gently(&refs->lock)) {
|
|
strbuf_addf(err, "unable to close %s: %s", refs->path, strerror(errno));
|
|
rollback_lock_file(&refs->lock);
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* There is a stat-validity problem might cause `update-ref -d`
|
|
* lost the newly commit of a ref, because a new `packed-refs`
|
|
* file might has the same on-disk file attributes such as
|
|
* timestamp, file size and inode value, but has a changed
|
|
* ref value.
|
|
*
|
|
* This could happen with a very small chance when
|
|
* `update-ref -d` is called and at the same time another
|
|
* `pack-refs --all` process is running.
|
|
*
|
|
* Now that we hold the `packed-refs` lock, it is important
|
|
* to make sure we could read the latest version of
|
|
* `packed-refs` file no matter we have just mmap it or not.
|
|
* So what need to do is clear the snapshot if we hold it
|
|
* already.
|
|
*/
|
|
clear_snapshot(refs);
|
|
|
|
/*
|
|
* Now make sure that the packed-refs file as it exists in the
|
|
* locked state is loaded into the snapshot:
|
|
*/
|
|
get_snapshot(refs);
|
|
return 0;
|
|
}
|
|
|
|
void packed_refs_unlock(struct ref_store *ref_store)
|
|
{
|
|
struct packed_ref_store *refs = packed_downcast(
|
|
ref_store,
|
|
REF_STORE_READ | REF_STORE_WRITE,
|
|
"packed_refs_unlock");
|
|
|
|
if (!is_lock_file_locked(&refs->lock))
|
|
BUG("packed_refs_unlock() called when not locked");
|
|
rollback_lock_file(&refs->lock);
|
|
}
|
|
|
|
int packed_refs_is_locked(struct ref_store *ref_store)
|
|
{
|
|
struct packed_ref_store *refs = packed_downcast(
|
|
ref_store,
|
|
REF_STORE_READ | REF_STORE_WRITE,
|
|
"packed_refs_is_locked");
|
|
|
|
return is_lock_file_locked(&refs->lock);
|
|
}
|
|
|
|
/*
|
|
* The packed-refs header line that we write out. Perhaps other traits
|
|
* will be added later.
|
|
*
|
|
* Note that earlier versions of Git used to parse these traits by
|
|
* looking for " trait " in the line. For this reason, the space after
|
|
* the colon and the trailing space are required.
|
|
*/
|
|
static const char PACKED_REFS_HEADER[] =
|
|
"# pack-refs with: peeled fully-peeled sorted \n";
|
|
|
|
static int packed_init_db(struct ref_store *ref_store UNUSED,
|
|
struct strbuf *err UNUSED)
|
|
{
|
|
/* Nothing to do. */
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Write the packed refs from the current snapshot to the packed-refs
|
|
* tempfile, incorporating any changes from `updates`. `updates` must
|
|
* be a sorted string list whose keys are the refnames and whose util
|
|
* values are `struct ref_update *`. On error, rollback the tempfile,
|
|
* write an error message to `err`, and return a nonzero value.
|
|
*
|
|
* The packfile must be locked before calling this function and will
|
|
* remain locked when it is done.
|
|
*/
|
|
static int write_with_updates(struct packed_ref_store *refs,
|
|
struct string_list *updates,
|
|
struct strbuf *err)
|
|
{
|
|
struct ref_iterator *iter = NULL;
|
|
size_t i;
|
|
int ok;
|
|
FILE *out;
|
|
struct strbuf sb = STRBUF_INIT;
|
|
char *packed_refs_path;
|
|
|
|
if (!is_lock_file_locked(&refs->lock))
|
|
BUG("write_with_updates() called while unlocked");
|
|
|
|
/*
|
|
* If packed-refs is a symlink, we want to overwrite the
|
|
* symlinked-to file, not the symlink itself. Also, put the
|
|
* staging file next to it:
|
|
*/
|
|
packed_refs_path = get_locked_file_path(&refs->lock);
|
|
strbuf_addf(&sb, "%s.new", packed_refs_path);
|
|
free(packed_refs_path);
|
|
refs->tempfile = create_tempfile(sb.buf);
|
|
if (!refs->tempfile) {
|
|
strbuf_addf(err, "unable to create file %s: %s",
|
|
sb.buf, strerror(errno));
|
|
strbuf_release(&sb);
|
|
return -1;
|
|
}
|
|
strbuf_release(&sb);
|
|
|
|
out = fdopen_tempfile(refs->tempfile, "w");
|
|
if (!out) {
|
|
strbuf_addf(err, "unable to fdopen packed-refs tempfile: %s",
|
|
strerror(errno));
|
|
goto error;
|
|
}
|
|
|
|
if (fprintf(out, "%s", PACKED_REFS_HEADER) < 0)
|
|
goto write_error;
|
|
|
|
/*
|
|
* We iterate in parallel through the current list of refs and
|
|
* the list of updates, processing an entry from at least one
|
|
* of the lists each time through the loop. When the current
|
|
* list of refs is exhausted, set iter to NULL. When the list
|
|
* of updates is exhausted, leave i set to updates->nr.
|
|
*/
|
|
iter = packed_ref_iterator_begin(&refs->base, "",
|
|
DO_FOR_EACH_INCLUDE_BROKEN);
|
|
if ((ok = ref_iterator_advance(iter)) != ITER_OK)
|
|
iter = NULL;
|
|
|
|
i = 0;
|
|
|
|
while (iter || i < updates->nr) {
|
|
struct ref_update *update = NULL;
|
|
int cmp;
|
|
|
|
if (i >= updates->nr) {
|
|
cmp = -1;
|
|
} else {
|
|
update = updates->items[i].util;
|
|
|
|
if (!iter)
|
|
cmp = +1;
|
|
else
|
|
cmp = strcmp(iter->refname, update->refname);
|
|
}
|
|
|
|
if (!cmp) {
|
|
/*
|
|
* There is both an old value and an update
|
|
* for this reference. Check the old value if
|
|
* necessary:
|
|
*/
|
|
if ((update->flags & REF_HAVE_OLD)) {
|
|
if (is_null_oid(&update->old_oid)) {
|
|
strbuf_addf(err, "cannot update ref '%s': "
|
|
"reference already exists",
|
|
update->refname);
|
|
goto error;
|
|
} else if (!oideq(&update->old_oid, iter->oid)) {
|
|
strbuf_addf(err, "cannot update ref '%s': "
|
|
"is at %s but expected %s",
|
|
update->refname,
|
|
oid_to_hex(iter->oid),
|
|
oid_to_hex(&update->old_oid));
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
/* Now figure out what to use for the new value: */
|
|
if ((update->flags & REF_HAVE_NEW)) {
|
|
/*
|
|
* The update takes precedence. Skip
|
|
* the iterator over the unneeded
|
|
* value.
|
|
*/
|
|
if ((ok = ref_iterator_advance(iter)) != ITER_OK)
|
|
iter = NULL;
|
|
cmp = +1;
|
|
} else {
|
|
/*
|
|
* The update doesn't actually want to
|
|
* change anything. We're done with it.
|
|
*/
|
|
i++;
|
|
cmp = -1;
|
|
}
|
|
} else if (cmp > 0) {
|
|
/*
|
|
* There is no old value but there is an
|
|
* update for this reference. Make sure that
|
|
* the update didn't expect an existing value:
|
|
*/
|
|
if ((update->flags & REF_HAVE_OLD) &&
|
|
!is_null_oid(&update->old_oid)) {
|
|
strbuf_addf(err, "cannot update ref '%s': "
|
|
"reference is missing but expected %s",
|
|
update->refname,
|
|
oid_to_hex(&update->old_oid));
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
if (cmp < 0) {
|
|
/* Pass the old reference through. */
|
|
|
|
struct object_id peeled;
|
|
int peel_error = ref_iterator_peel(iter, &peeled);
|
|
|
|
if (write_packed_entry(out, iter->refname,
|
|
iter->oid,
|
|
peel_error ? NULL : &peeled))
|
|
goto write_error;
|
|
|
|
if ((ok = ref_iterator_advance(iter)) != ITER_OK)
|
|
iter = NULL;
|
|
} else if (is_null_oid(&update->new_oid)) {
|
|
/*
|
|
* The update wants to delete the reference,
|
|
* and the reference either didn't exist or we
|
|
* have already skipped it. So we're done with
|
|
* the update (and don't have to write
|
|
* anything).
|
|
*/
|
|
i++;
|
|
} else {
|
|
struct object_id peeled;
|
|
int peel_error = peel_object(&update->new_oid,
|
|
&peeled);
|
|
|
|
if (write_packed_entry(out, update->refname,
|
|
&update->new_oid,
|
|
peel_error ? NULL : &peeled))
|
|
goto write_error;
|
|
|
|
i++;
|
|
}
|
|
}
|
|
|
|
if (ok != ITER_DONE) {
|
|
strbuf_addstr(err, "unable to write packed-refs file: "
|
|
"error iterating over old contents");
|
|
goto error;
|
|
}
|
|
|
|
if (fflush(out) ||
|
|
fsync_component(FSYNC_COMPONENT_REFERENCE, get_tempfile_fd(refs->tempfile)) ||
|
|
close_tempfile_gently(refs->tempfile)) {
|
|
strbuf_addf(err, "error closing file %s: %s",
|
|
get_tempfile_path(refs->tempfile),
|
|
strerror(errno));
|
|
strbuf_release(&sb);
|
|
delete_tempfile(&refs->tempfile);
|
|
return -1;
|
|
}
|
|
|
|
return 0;
|
|
|
|
write_error:
|
|
strbuf_addf(err, "error writing to %s: %s",
|
|
get_tempfile_path(refs->tempfile), strerror(errno));
|
|
|
|
error:
|
|
if (iter)
|
|
ref_iterator_abort(iter);
|
|
|
|
delete_tempfile(&refs->tempfile);
|
|
return -1;
|
|
}
|
|
|
|
int is_packed_transaction_needed(struct ref_store *ref_store,
|
|
struct ref_transaction *transaction)
|
|
{
|
|
struct packed_ref_store *refs = packed_downcast(
|
|
ref_store,
|
|
REF_STORE_READ,
|
|
"is_packed_transaction_needed");
|
|
struct strbuf referent = STRBUF_INIT;
|
|
size_t i;
|
|
int ret;
|
|
|
|
if (!is_lock_file_locked(&refs->lock))
|
|
BUG("is_packed_transaction_needed() called while unlocked");
|
|
|
|
/*
|
|
* We're only going to bother returning false for the common,
|
|
* trivial case that references are only being deleted, their
|
|
* old values are not being checked, and the old `packed-refs`
|
|
* file doesn't contain any of those reference(s). This gives
|
|
* false positives for some other cases that could
|
|
* theoretically be optimized away:
|
|
*
|
|
* 1. It could be that the old value is being verified without
|
|
* setting a new value. In this case, we could verify the
|
|
* old value here and skip the update if it agrees. If it
|
|
* disagrees, we could either let the update go through
|
|
* (the actual commit would re-detect and report the
|
|
* problem), or come up with a way of reporting such an
|
|
* error to *our* caller.
|
|
*
|
|
* 2. It could be that a new value is being set, but that it
|
|
* is identical to the current packed value of the
|
|
* reference.
|
|
*
|
|
* Neither of these cases will come up in the current code,
|
|
* because the only caller of this function passes to it a
|
|
* transaction that only includes `delete` updates with no
|
|
* `old_id`. Even if that ever changes, false positives only
|
|
* cause an optimization to be missed; they do not affect
|
|
* correctness.
|
|
*/
|
|
|
|
/*
|
|
* Start with the cheap checks that don't require old
|
|
* reference values to be read:
|
|
*/
|
|
for (i = 0; i < transaction->nr; i++) {
|
|
struct ref_update *update = transaction->updates[i];
|
|
|
|
if (update->flags & REF_HAVE_OLD)
|
|
/* Have to check the old value -> needed. */
|
|
return 1;
|
|
|
|
if ((update->flags & REF_HAVE_NEW) && !is_null_oid(&update->new_oid))
|
|
/* Have to set a new value -> needed. */
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* The transaction isn't checking any old values nor is it
|
|
* setting any nonzero new values, so it still might be able
|
|
* to be skipped. Now do the more expensive check: the update
|
|
* is needed if any of the updates is a delete, and the old
|
|
* `packed-refs` file contains a value for that reference.
|
|
*/
|
|
ret = 0;
|
|
for (i = 0; i < transaction->nr; i++) {
|
|
struct ref_update *update = transaction->updates[i];
|
|
int failure_errno;
|
|
unsigned int type;
|
|
struct object_id oid;
|
|
|
|
if (!(update->flags & REF_HAVE_NEW))
|
|
/*
|
|
* This reference isn't being deleted -> not
|
|
* needed.
|
|
*/
|
|
continue;
|
|
|
|
if (!refs_read_raw_ref(ref_store, update->refname, &oid,
|
|
&referent, &type, &failure_errno) ||
|
|
failure_errno != ENOENT) {
|
|
/*
|
|
* We have to actually delete that reference
|
|
* -> this transaction is needed.
|
|
*/
|
|
ret = 1;
|
|
break;
|
|
}
|
|
}
|
|
|
|
strbuf_release(&referent);
|
|
return ret;
|
|
}
|
|
|
|
struct packed_transaction_backend_data {
|
|
/* True iff the transaction owns the packed-refs lock. */
|
|
int own_lock;
|
|
|
|
struct string_list updates;
|
|
};
|
|
|
|
static void packed_transaction_cleanup(struct packed_ref_store *refs,
|
|
struct ref_transaction *transaction)
|
|
{
|
|
struct packed_transaction_backend_data *data = transaction->backend_data;
|
|
|
|
if (data) {
|
|
string_list_clear(&data->updates, 0);
|
|
|
|
if (is_tempfile_active(refs->tempfile))
|
|
delete_tempfile(&refs->tempfile);
|
|
|
|
if (data->own_lock && is_lock_file_locked(&refs->lock)) {
|
|
packed_refs_unlock(&refs->base);
|
|
data->own_lock = 0;
|
|
}
|
|
|
|
free(data);
|
|
transaction->backend_data = NULL;
|
|
}
|
|
|
|
transaction->state = REF_TRANSACTION_CLOSED;
|
|
}
|
|
|
|
static int packed_transaction_prepare(struct ref_store *ref_store,
|
|
struct ref_transaction *transaction,
|
|
struct strbuf *err)
|
|
{
|
|
struct packed_ref_store *refs = packed_downcast(
|
|
ref_store,
|
|
REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB,
|
|
"ref_transaction_prepare");
|
|
struct packed_transaction_backend_data *data;
|
|
size_t i;
|
|
int ret = TRANSACTION_GENERIC_ERROR;
|
|
|
|
/*
|
|
* Note that we *don't* skip transactions with zero updates,
|
|
* because such a transaction might be executed for the side
|
|
* effect of ensuring that all of the references are peeled or
|
|
* ensuring that the `packed-refs` file is sorted. If the
|
|
* caller wants to optimize away empty transactions, it should
|
|
* do so itself.
|
|
*/
|
|
|
|
CALLOC_ARRAY(data, 1);
|
|
string_list_init_nodup(&data->updates);
|
|
|
|
transaction->backend_data = data;
|
|
|
|
/*
|
|
* Stick the updates in a string list by refname so that we
|
|
* can sort them:
|
|
*/
|
|
for (i = 0; i < transaction->nr; i++) {
|
|
struct ref_update *update = transaction->updates[i];
|
|
struct string_list_item *item =
|
|
string_list_append(&data->updates, update->refname);
|
|
|
|
/* Store a pointer to update in item->util: */
|
|
item->util = update;
|
|
}
|
|
string_list_sort(&data->updates);
|
|
|
|
if (ref_update_reject_duplicates(&data->updates, err))
|
|
goto failure;
|
|
|
|
if (!is_lock_file_locked(&refs->lock)) {
|
|
if (packed_refs_lock(ref_store, 0, err))
|
|
goto failure;
|
|
data->own_lock = 1;
|
|
}
|
|
|
|
if (write_with_updates(refs, &data->updates, err))
|
|
goto failure;
|
|
|
|
transaction->state = REF_TRANSACTION_PREPARED;
|
|
return 0;
|
|
|
|
failure:
|
|
packed_transaction_cleanup(refs, transaction);
|
|
return ret;
|
|
}
|
|
|
|
static int packed_transaction_abort(struct ref_store *ref_store,
|
|
struct ref_transaction *transaction,
|
|
struct strbuf *err UNUSED)
|
|
{
|
|
struct packed_ref_store *refs = packed_downcast(
|
|
ref_store,
|
|
REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB,
|
|
"ref_transaction_abort");
|
|
|
|
packed_transaction_cleanup(refs, transaction);
|
|
return 0;
|
|
}
|
|
|
|
static int packed_transaction_finish(struct ref_store *ref_store,
|
|
struct ref_transaction *transaction,
|
|
struct strbuf *err)
|
|
{
|
|
struct packed_ref_store *refs = packed_downcast(
|
|
ref_store,
|
|
REF_STORE_READ | REF_STORE_WRITE | REF_STORE_ODB,
|
|
"ref_transaction_finish");
|
|
int ret = TRANSACTION_GENERIC_ERROR;
|
|
char *packed_refs_path;
|
|
|
|
clear_snapshot(refs);
|
|
|
|
packed_refs_path = get_locked_file_path(&refs->lock);
|
|
if (rename_tempfile(&refs->tempfile, packed_refs_path)) {
|
|
strbuf_addf(err, "error replacing %s: %s",
|
|
refs->path, strerror(errno));
|
|
goto cleanup;
|
|
}
|
|
|
|
ret = 0;
|
|
|
|
cleanup:
|
|
free(packed_refs_path);
|
|
packed_transaction_cleanup(refs, transaction);
|
|
return ret;
|
|
}
|
|
|
|
static int packed_initial_transaction_commit(struct ref_store *ref_store UNUSED,
|
|
struct ref_transaction *transaction,
|
|
struct strbuf *err)
|
|
{
|
|
return ref_transaction_commit(transaction, err);
|
|
}
|
|
|
|
static int packed_delete_refs(struct ref_store *ref_store, const char *msg,
|
|
struct string_list *refnames, unsigned int flags)
|
|
{
|
|
struct packed_ref_store *refs =
|
|
packed_downcast(ref_store, REF_STORE_WRITE, "delete_refs");
|
|
struct strbuf err = STRBUF_INIT;
|
|
struct ref_transaction *transaction;
|
|
struct string_list_item *item;
|
|
int ret;
|
|
|
|
(void)refs; /* We need the check above, but don't use the variable */
|
|
|
|
if (!refnames->nr)
|
|
return 0;
|
|
|
|
/*
|
|
* Since we don't check the references' old_oids, the
|
|
* individual updates can't fail, so we can pack all of the
|
|
* updates into a single transaction.
|
|
*/
|
|
|
|
transaction = ref_store_transaction_begin(ref_store, &err);
|
|
if (!transaction)
|
|
return -1;
|
|
|
|
for_each_string_list_item(item, refnames) {
|
|
if (ref_transaction_delete(transaction, item->string, NULL,
|
|
flags, msg, &err)) {
|
|
warning(_("could not delete reference %s: %s"),
|
|
item->string, err.buf);
|
|
strbuf_reset(&err);
|
|
}
|
|
}
|
|
|
|
ret = ref_transaction_commit(transaction, &err);
|
|
|
|
if (ret) {
|
|
if (refnames->nr == 1)
|
|
error(_("could not delete reference %s: %s"),
|
|
refnames->items[0].string, err.buf);
|
|
else
|
|
error(_("could not delete references: %s"), err.buf);
|
|
}
|
|
|
|
ref_transaction_free(transaction);
|
|
strbuf_release(&err);
|
|
return ret;
|
|
}
|
|
|
|
static int packed_pack_refs(struct ref_store *ref_store UNUSED,
|
|
unsigned int flags UNUSED)
|
|
{
|
|
/*
|
|
* Packed refs are already packed. It might be that loose refs
|
|
* are packed *into* a packed refs store, but that is done by
|
|
* updating the packed references via a transaction.
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *ref_store UNUSED)
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{
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return empty_ref_iterator_begin();
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}
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struct ref_storage_be refs_be_packed = {
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.next = NULL,
|
|
.name = "packed",
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.init = packed_ref_store_create,
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.init_db = packed_init_db,
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.transaction_prepare = packed_transaction_prepare,
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|
.transaction_finish = packed_transaction_finish,
|
|
.transaction_abort = packed_transaction_abort,
|
|
.initial_transaction_commit = packed_initial_transaction_commit,
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|
|
|
.pack_refs = packed_pack_refs,
|
|
.create_symref = NULL,
|
|
.delete_refs = packed_delete_refs,
|
|
.rename_ref = NULL,
|
|
.copy_ref = NULL,
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|
|
|
.iterator_begin = packed_ref_iterator_begin,
|
|
.read_raw_ref = packed_read_raw_ref,
|
|
.read_symbolic_ref = NULL,
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|
|
|
.reflog_iterator_begin = packed_reflog_iterator_begin,
|
|
.for_each_reflog_ent = NULL,
|
|
.for_each_reflog_ent_reverse = NULL,
|
|
.reflog_exists = NULL,
|
|
.create_reflog = NULL,
|
|
.delete_reflog = NULL,
|
|
.reflog_expire = NULL,
|
|
};
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