It is sometimes useful to reduce the size of a `string_list`'s list of
items without having to re-allocate them. For example, doing the
following:
struct strbuf buf = STRBUF_INIT;
struct string_list parts = STRING_LIST_INIT_NO_DUP;
while (strbuf_getline(&buf, stdin) != EOF) {
parts.nr = 0;
string_list_split_in_place(&parts, buf.buf, ":", -1);
/* ... */
}
string_list_clear(&parts, 0);
is preferable over calling `string_list_clear()` on every iteration of
the loop. This is because `string_list_clear()` causes us free our
existing `items` array. This means that every time we call
`string_list_split_in_place()`, the string-list internals re-allocate
the same size array.
Since in the above example we do not care about the individual parts
after processing each line, it is much more efficient to pretend that
there aren't any elements in the `string_list` by setting `list->nr` to
0 while leaving the list of elements allocated as-is.
This allows `string_list_split_in_place()` to overwrite any existing
entries without needing to free and re-allocate them.
However, setting `list->nr` manually is not safe in all instances. There
are a couple of cases worth worrying about:
- If the `string_list` is initialized with `strdup_strings`,
truncating the list can lead to overwriting strings which are
allocated elsewhere. If there aren't any other pointers to those
strings other than the ones inside of the `items` array, they will
become unreachable and leak.
(We could ourselves free the truncated items between
string_list->items[nr] and `list->nr`, but no present or future
callers would benefit from this additional complexity).
- If the given `nr` is larger than the current value of `list->nr`,
we'll trick the `string_list` into a state where it thinks there are
more items allocated than there actually are, which can lead to
undefined behavior if we try to read or write those entries.
Guard against both of these by introducing a helper function which
guards assignment of `list->nr` against each of the above conditions.
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Enhance `string_list_split_in_place()` to accept multiple characters as
delimiters instead of a single character.
Instead of using `strchr(2)` to locate the first occurrence of the given
delimiter character, `string_list_split_in_place_multi()` uses
`strcspn(2)` to move past the initial segment of characters comprised of
any characters in the delimiting set.
When only a single delimiting character is provided, `strpbrk(2)` (which
is implemented with `strcspn(2)`) has equivalent performance to
`strchr(2)`. Modern `strcspn(2)` implementations treat an empty
delimiter or the singleton delimiter as a special case and fall back to
calling strchrnul(). Both glibc[1] and musl[2] implement `strcspn(2)`
this way.
This change is one step to removing `strtok(2)` from the tree. Note that
`string_list_split_in_place()` is not a strict replacement for
`strtok()`, since it will happily turn sequential delimiter characters
into empty entries in the resulting string_list. For example:
string_list_split_in_place(&xs, "foo:;:bar:;:baz", ":;", -1)
would yield a string list of:
["foo", "", "", "bar", "", "", "baz"]
Callers that wish to emulate the behavior of strtok(2) more directly
should call `string_list_remove_empty_items()` after splitting.
To avoid regressions for the new multi-character delimter cases, update
t0063 in this patch as well.
[1]: https://sourceware.org/git/?p=glibc.git;a=blob;f=string/strcspn.c;hb=glibc-2.37#l35
[2]: https://git.musl-libc.org/cgit/musl/tree/src/string/strcspn.c?h=v1.2.3#n11
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This allows us to replace includes of cache.h with includes of the much
smaller alloc.h in many places. It does mean that we also need to add
includes of alloc.h in a number of C files.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
String-lists may be used with callbacks for clearing or iteration. These
callbacks need to conform to a particular interface, even though not
every callback needs all of its parameters. Mark the unused ones to make
-Wunused-parameter happy.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Remove this function left over to accommodate in-flight changes, see
770fedaf9f (string-list.[ch]: add a string_list_init_{nodup,dup}(),
2021-07-01) for the recent change to add
"string_list_init_{nodup,dup}()" initializers.
There was only one user of the API left in remote-curl.c. I don't know
why I didn't include this change to remote-curl.c in
bc40dfb10a (string-list.h users: change to use *_{nodup,dup}(),
2021-07-01), perhaps I just missed it.
In any case, let's change that one user to use the new API, as of
writing this there are no in-flight changes that use, so this seems
like a good time to drop this before we get any new users of this
compatibility API.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In order to use the new "memcpy() a 'blank' struct on the stack"
pattern for string_list_init(), and to make the macro initialization
consistent with the function initialization introduce two new
string_list_init_{nodup,dup}() functions. These are like the old
string_list_init() when called with a false and true second argument,
respectively.
I think this not only makes things more consistent, but also easier to
read. I often had to lookup what the ", 0)" or ", 1)" in these
invocations meant, now it's right there in the function name, and
corresponds to the macros.
A subsequent commit will convert existing API users to this pattern,
but as this is a very common API let's leave a compatibility function
in place for later removal. This intermediate state also proves that
the compatibility function works.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A removal of this helper function was proposed 3 years ago [1]; the
function was never used since it was introduced in 2006 back then,
and there is no new callers since. Now time has proven we really do
not need the function.
[1] https://public-inbox.org/git/1421343725-3973-1-git-send-email-kuleshovmail@gmail.com/
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
ISO C forbids the conversion of void pointers to function pointers.
Introduce a context struct that encapsulates the function pointer.
Signed-off-by: Beat Bolli <dev+git@drbeat.li>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A common mistake when writing binary search is to allow possible
integer overflow by using the simple average:
mid = (min + max) / 2;
Instead, use the overflow-safe version:
mid = min + (max - min) / 2;
This translation is safe since the operation occurs inside a loop
conditioned on "min < max". The included changes were found using
the following git grep:
git grep '/ *2;' '*.c'
Making this cleanup will prevent future review friction when a new
binary search is contructed based on existing code.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Simplify the code for moving members inside of an array and make it more
robust by using the helper macro MOVE_ARRAY. It calculates the size
based on the specified number of elements for us and supports NULL
pointers when that number is zero. Raw memmove(3) calls with NULL can
cause the compiler to (over-eagerly) optimize out later NULL checks.
This patch was generated with contrib/coccinelle/array.cocci and spatch
(Coccinelle).
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "run-command" API implementation has been made more robust
against dead-locking in a threaded environment.
* bw/forking-and-threading:
usage.c: drop set_error_handle()
run-command: restrict PATH search to executable files
run-command: expose is_executable function
run-command: block signals between fork and execve
run-command: add note about forking and threading
run-command: handle dup2 and close errors in child
run-command: eliminate calls to error handling functions in child
run-command: don't die in child when duping /dev/null
run-command: prepare child environment before forking
string-list: add string_list_remove function
run-command: use the async-signal-safe execv instead of execvp
run-command: prepare command before forking
t0061: run_command executes scripts without a #! line
t5550: use write_script to generate post-update hook
The string-list API used a custom reallocation strategy that was
very inefficient, instead of using the usual ALLOC_GROW() macro,
which has been fixed.
* jh/string-list-micro-optim:
string-list: use ALLOC_GROW macro when reallocing string_list
Teach string-list to be able to remove a string from a sorted
'struct string_list'.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Use ALLOC_GROW() macro when reallocing a string_list array
rather than simply increasing it by 32. This is a performance
optimization.
During status on a very large repo and there are many changes,
a significant percentage of the total run time is spent
reallocing the wt_status.changes array.
This change decreases the time in wt_status_collect_changes_worktree()
from 125 seconds to 45 seconds on my very large repository.
This produced a modest gain on my 1M file artificial repo, but
broke even on linux.git.
Test HEAD^^ HEAD
---------------------------------------------------------------------------------------
0005.2: read-tree status br_ballast (1000001) 8.29(5.62+2.62) 8.22(5.57+2.63) -0.8%
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Pass the comparison function to cmp_items() via the context parameter of
qsort_s() instead of using a global variable. That allows calling
string_list_sort() from multiple parallel threads.
Our qsort_s() in compat/ is slightly slower than qsort(1) from glibc
2.24 for sorting lots of lines:
Test HEAD^ HEAD
---------------------------------------------------------------------
0071.2: sort(1) 0.10(0.22+0.01) 0.09(0.21+0.00) -10.0%
0071.3: string_list_sort() 0.16(0.15+0.01) 0.17(0.15+0.00) +6.3%
GNU sort(1) version 8.26 is significantly faster because it uses
multiple parallel threads; with the unportable option --parallel=1 it
becomes slower:
Test HEAD^ HEAD
--------------------------------------------------------------------
0071.2: sort(1) 0.21(0.18+0.01) 0.20(0.18+0.01) -4.8%
0071.3: string_list_sort() 0.16(0.13+0.02) 0.17(0.15+0.01) +6.3%
There is some instability -- the numbers for the sort(1) check shouldn't
be affected by this patch. Anyway, the performance of our qsort_s()
implementation is apparently good enough, at least for this test.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Apply the semantic patch contrib/coccinelle/qsort.cocci to the code
base, replacing calls of qsort(3) with QSORT. The resulting code is
shorter and supports empty arrays with NULL pointers.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Using the string-list API in function unsorted_string_list_lookup()
makes the code more readable.
Signed-off-by: Ralf Thielow <ralf.thielow@gmail.com>
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
API simplification.
* sb/string-list:
string_list: remove string_list_insert_at_index() from its API
mailmap: use higher level string list functions
string_list: document string_list_(insert,lookup)
The new name is more consistent with the names of other
string_list-related functions.
Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The string-list API has STRING_LIST_INIT_* macros to be used
to define variables with initializers, but lacks functions
to initialize an uninitialized piece of memory to be used as
a string-list at the run-time.
Introduce `string_list_init()` function for that.
Signed-off-by: Tanay Abhra <tanayabh@gmail.com>
Reviewed-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach commands in the "log" family to optionally pay attention to
the mailmap.
* ap/log-mailmap:
log --use-mailmap: optimize for cases without --author/--committer search
log: add log.mailmap configuration option
log: grep author/committer using mailmap
test: add test for --use-mailmap option
log: add --use-mailmap option
pretty: use mailmap to display username and email
mailmap: add mailmap structure to rev_info and pp
mailmap: simplify map_user() interface
mailmap: remove email copy and length limitation
Use split_ident_line to parse author and committer
string-list: allow case-insensitive string list
Some string list needs to be searched case insensitively, and for
that to work correctly, the string needs to be sorted case
insensitively from the beginning.
Allow a custom comparison function to be defined on a string list
instance and use it throughout in place of strcmp().
Signed-off-by: Junio C Hamano <gitster@pobox.com>
An element on GIT_CEILING_DIRECTORIES list that does not name the
real path to a directory (i.e. a symbolic link) could have caused
the GIT_DIR discovery logic to escape the ceiling.
* mh/ceiling:
string_list_longest_prefix(): remove function
setup_git_directory_gently_1(): resolve symlinks in ceiling paths
longest_ancestor_length(): require prefix list entries to be normalized
longest_ancestor_length(): take a string_list argument for prefixes
longest_ancestor_length(): use string_list_split()
Introduce new function real_path_if_valid()
real_path_internal(): add comment explaining use of cwd
Introduce new static function real_path_internal()
This function was added in f103f95b11 in
the erroneous expectation that it would be used in the
reimplementation of longest_ancestor_length(). But it turned out to
be easier to use a function specialized for comparing path prefixes
(i.e., one that knows about slashes and root paths) than to prepare
the paths in such a way that a generic string prefix comparison
function can be used. So delete string_list_longest_prefix() and its
documentation and test cases.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jeff King <peff@peff.net>
Add a function that finds the longest string from a string_list that
is a prefix of a given string.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a function that deletes duplicate entries from a sorted
string_list.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This function allows entries that don't match a specified criterion to
be discarded from a string_list while preserving the order of the
remaining entries.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add two new functions, string_list_split() and
string_list_split_in_place(). These split a string into a string_list
on a separator character. The first makes copies of the substrings
(leaving the input string untouched) and the second splits the
original string in place, overwriting the separator characters with
NULs and referring to the original string's memory.
These functions are similar to the strbuf_split_*() functions except
that they work with the more powerful string_list interface.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a new function that appends a string to a string_list without
copying it. This can be used to pass ownership of an already-copied
string to a string_list that has strdup_strings set.
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Teach the string-list API how to remove an entry in O(1) runtime by
moving the last entry to the vacated spot. As such, the routine works
only for unsorted lists.
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
It is not immediately obvious that the util field may
contain random bytes after appending an item. Especially
since the string_list_insert* functions _do_ explicitly zero
the util pointer.
This does not appear to be a bug in any current git code, as
all callers either fill in the util field immediately or
never use it. However, it is worth it to be less surprising
to new users of the string-list API who may expect it to be
intialized to NULL.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update the definition and callers of string_list_append to use the
string_list as the first argument. This helps make the string_list
API easier to use by being more consistent.
Signed-off-by: Julian Phillips <julian@quantumfyre.co.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update the definition and callers of string_list_lookup to use the
string_list as the first argument. This helps make the string_list
API easier to use by being more consistent.
Signed-off-by: Julian Phillips <julian@quantumfyre.co.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update the definition and callers of string_list_insert_at_index to
use the string_list as the first argument. This helps make the
string_list API easier to use by being more consistent.
Signed-off-by: Julian Phillips <julian@quantumfyre.co.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update the definition and callers of string_list_insert to use the
string_list as the first argument. This helps make the string_list
API easier to use by being more consistent.
Signed-off-by: Julian Phillips <julian@quantumfyre.co.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update the definition and callers of for_each_string_list to use the
string_list as the first argument. This helps make the string_list
API easier to use by being more consistent.
Signed-off-by: Julian Phillips <julian@quantumfyre.co.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Update the definition and callers of print_string_list to use the
string_list as the first argument. This helps make the API easier to
use by being more consistent.
Signed-off-by: Julian Phillips <julian@quantumfyre.co.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Sometimes users need to lookup a string in an unsorted string_list. In
that case they should use this function instead of the version for
sorted strings.
Signed-off-by: Stephen Boyd <bebarino@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Add a convenience function for iterating over a string_list's items via
a callback.
Signed-off-by: Jay Soffian <jaysoffian@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
string_list_find_insert_index() and string_list_insert_at_index()
enables you to see if an item is in the string_list, and to
insert at the appropriate index in the list, if not there.
This is usefull if you need to manipulate an existing item,
if present, and insert a new item if not.
Future mailmap code will use this construct to enable
complex (old_name, old_email) -> (new_name, new_email)
lookups.
The string_list_clear_func() allows to call a custom
cleanup function on each item in a string_list, which is
useful is the util member points to a complex structure.
Signed-off-by: Marius Storm-Olsen <marius@trolltech.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The name path_list was correct for the first usage of that data structure,
but it really is a general-purpose string list.
$ perl -i -pe 's/path-list/string-list/g' $(git grep -l path-list)
$ perl -i -pe 's/path_list/string_list/g' $(git grep -l path_list)
$ git mv path-list.h string-list.h
$ git mv path-list.c string-list.c
$ perl -i -pe 's/has_path/has_string/g' $(git grep -l has_path)
$ perl -i -pe 's/path/string/g' string-list.[ch]
$ git mv Documentation/technical/api-path-list.txt \
Documentation/technical/api-string-list.txt
$ perl -i -pe 's/strdup_paths/strdup_strings/g' $(git grep -l strdup_paths)
... and then fix all users of string-list to access the member "string"
instead of "path".
Documentation/technical/api-string-list.txt needed some rewrapping, too.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
