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![Jeff King](/assets/img/avatar_default.png)
The diff code represents paths using the diff_filespec struct. This struct has a sha1 to represent the sha1 of the content at that path, as well as a sha1_valid member which indicates whether its sha1 field is actually useful. If sha1_valid is not true, then the filespec represents a working tree file (e.g., for the no-index case, or for when the index is not up-to-date). The diff_filespec is only used internally, though. At the interfaces to the diff subsystem, callers feed the sha1 directly, and we create a diff_filespec from it. It's at that point that we look at the sha1 and decide whether it is valid or not; callers may pass the null sha1 as a sentinel value to indicate that it is not. We should not typically see the null sha1 coming from any other source (e.g., in the index itself, or from a tree). However, a corrupt tree might have a null sha1, which would cause "diff --patch" to accidentally diff the working tree version of a file instead of treating it as a blob. This patch extends the edges of the diff interface to accept a "sha1_valid" flag whenever we accept a sha1, and to use that flag when creating a filespec. In some cases, this means passing the flag through several layers, making the code change larger than would be desirable. One alternative would be to simply die() upon seeing corrupted trees with null sha1s. However, this fix more directly addresses the problem (while bogus sha1s in a tree are probably a bad thing, it is really the sentinel confusion sending us down the wrong code path that is what makes it devastating). And it means that git is more capable of examining and debugging these corrupted trees. For example, you can still "diff --raw" such a tree to find out when the bogus entry was introduced; you just cannot do a "--patch" diff (just as you could not with any other corrupted tree, as we do not have any content to diff). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
528 lines
14 KiB
C
528 lines
14 KiB
C
/*
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* Copyright (C) 2005 Junio C Hamano
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*/
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#include "cache.h"
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#include "quote.h"
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#include "commit.h"
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#include "diff.h"
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#include "diffcore.h"
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#include "revision.h"
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#include "cache-tree.h"
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#include "unpack-trees.h"
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#include "refs.h"
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#include "submodule.h"
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/*
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* diff-files
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*/
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/*
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* Has the work tree entity been removed?
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*
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* Return 1 if it was removed from the work tree, 0 if an entity to be
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* compared with the cache entry ce still exists (the latter includes
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* the case where a directory that is not a submodule repository
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* exists for ce that is a submodule -- it is a submodule that is not
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* checked out). Return negative for an error.
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*/
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static int check_removed(const struct cache_entry *ce, struct stat *st)
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{
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if (lstat(ce->name, st) < 0) {
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if (errno != ENOENT && errno != ENOTDIR)
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return -1;
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return 1;
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}
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if (has_symlink_leading_path(ce->name, ce_namelen(ce)))
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return 1;
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if (S_ISDIR(st->st_mode)) {
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unsigned char sub[20];
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/*
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* If ce is already a gitlink, we can have a plain
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* directory (i.e. the submodule is not checked out),
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* or a checked out submodule. Either case this is not
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* a case where something was removed from the work tree,
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* so we will return 0.
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*
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* Otherwise, if the directory is not a submodule
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* repository, that means ce which was a blob turned into
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* a directory --- the blob was removed!
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*/
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if (!S_ISGITLINK(ce->ce_mode) &&
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resolve_gitlink_ref(ce->name, "HEAD", sub))
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return 1;
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}
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return 0;
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}
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/*
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* Has a file changed or has a submodule new commits or a dirty work tree?
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*
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* Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES
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* option is set, the caller does not only want to know if a submodule is
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* modified at all but wants to know all the conditions that are met (new
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* commits, untracked content and/or modified content).
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*/
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static int match_stat_with_submodule(struct diff_options *diffopt,
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struct cache_entry *ce, struct stat *st,
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unsigned ce_option, unsigned *dirty_submodule)
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{
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int changed = ce_match_stat(ce, st, ce_option);
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if (S_ISGITLINK(ce->ce_mode)) {
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unsigned orig_flags = diffopt->flags;
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if (!DIFF_OPT_TST(diffopt, OVERRIDE_SUBMODULE_CONFIG))
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set_diffopt_flags_from_submodule_config(diffopt, ce->name);
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if (DIFF_OPT_TST(diffopt, IGNORE_SUBMODULES))
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changed = 0;
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else if (!DIFF_OPT_TST(diffopt, IGNORE_DIRTY_SUBMODULES)
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&& (!changed || DIFF_OPT_TST(diffopt, DIRTY_SUBMODULES)))
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*dirty_submodule = is_submodule_modified(ce->name, DIFF_OPT_TST(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES));
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diffopt->flags = orig_flags;
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}
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return changed;
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}
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int run_diff_files(struct rev_info *revs, unsigned int option)
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{
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int entries, i;
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int diff_unmerged_stage = revs->max_count;
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int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
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unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
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? CE_MATCH_RACY_IS_DIRTY : 0);
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diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
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if (diff_unmerged_stage < 0)
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diff_unmerged_stage = 2;
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entries = active_nr;
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for (i = 0; i < entries; i++) {
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struct stat st;
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unsigned int oldmode, newmode;
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struct cache_entry *ce = active_cache[i];
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int changed;
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unsigned dirty_submodule = 0;
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if (diff_can_quit_early(&revs->diffopt))
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break;
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if (!ce_path_match(ce, &revs->prune_data))
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continue;
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if (ce_stage(ce)) {
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struct combine_diff_path *dpath;
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struct diff_filepair *pair;
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unsigned int wt_mode = 0;
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int num_compare_stages = 0;
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size_t path_len;
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path_len = ce_namelen(ce);
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dpath = xmalloc(combine_diff_path_size(5, path_len));
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dpath->path = (char *) &(dpath->parent[5]);
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dpath->next = NULL;
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dpath->len = path_len;
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memcpy(dpath->path, ce->name, path_len);
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dpath->path[path_len] = '\0';
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hashclr(dpath->sha1);
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memset(&(dpath->parent[0]), 0,
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sizeof(struct combine_diff_parent)*5);
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changed = check_removed(ce, &st);
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if (!changed)
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wt_mode = ce_mode_from_stat(ce, st.st_mode);
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else {
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if (changed < 0) {
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perror(ce->name);
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continue;
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}
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if (silent_on_removed)
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continue;
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wt_mode = 0;
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}
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dpath->mode = wt_mode;
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while (i < entries) {
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struct cache_entry *nce = active_cache[i];
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int stage;
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if (strcmp(ce->name, nce->name))
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break;
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/* Stage #2 (ours) is the first parent,
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* stage #3 (theirs) is the second.
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*/
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stage = ce_stage(nce);
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if (2 <= stage) {
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int mode = nce->ce_mode;
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num_compare_stages++;
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hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
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dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
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dpath->parent[stage-2].status =
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DIFF_STATUS_MODIFIED;
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}
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/* diff against the proper unmerged stage */
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if (stage == diff_unmerged_stage)
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ce = nce;
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i++;
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}
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/*
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* Compensate for loop update
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*/
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i--;
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if (revs->combine_merges && num_compare_stages == 2) {
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show_combined_diff(dpath, 2,
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revs->dense_combined_merges,
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revs);
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free(dpath);
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continue;
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}
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free(dpath);
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dpath = NULL;
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/*
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* Show the diff for the 'ce' if we found the one
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* from the desired stage.
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*/
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pair = diff_unmerge(&revs->diffopt, ce->name);
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if (wt_mode)
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pair->two->mode = wt_mode;
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if (ce_stage(ce) != diff_unmerged_stage)
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continue;
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}
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if (ce_uptodate(ce) || ce_skip_worktree(ce))
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continue;
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/* If CE_VALID is set, don't look at workdir for file removal */
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changed = (ce->ce_flags & CE_VALID) ? 0 : check_removed(ce, &st);
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if (changed) {
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if (changed < 0) {
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perror(ce->name);
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continue;
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}
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if (silent_on_removed)
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continue;
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diff_addremove(&revs->diffopt, '-', ce->ce_mode,
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ce->sha1, !is_null_sha1(ce->sha1),
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ce->name, 0);
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continue;
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}
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changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
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ce_option, &dirty_submodule);
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if (!changed && !dirty_submodule) {
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ce_mark_uptodate(ce);
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if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
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continue;
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}
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oldmode = ce->ce_mode;
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newmode = ce_mode_from_stat(ce, st.st_mode);
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diff_change(&revs->diffopt, oldmode, newmode,
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ce->sha1, (changed ? null_sha1 : ce->sha1),
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!is_null_sha1(ce->sha1), (changed ? 0 : !is_null_sha1(ce->sha1)),
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ce->name, 0, dirty_submodule);
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}
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diffcore_std(&revs->diffopt);
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diff_flush(&revs->diffopt);
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return 0;
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}
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/*
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* diff-index
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*/
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/* A file entry went away or appeared */
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static void diff_index_show_file(struct rev_info *revs,
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const char *prefix,
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struct cache_entry *ce,
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const unsigned char *sha1, int sha1_valid,
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unsigned int mode,
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unsigned dirty_submodule)
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{
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diff_addremove(&revs->diffopt, prefix[0], mode,
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sha1, sha1_valid, ce->name, dirty_submodule);
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}
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static int get_stat_data(struct cache_entry *ce,
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const unsigned char **sha1p,
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unsigned int *modep,
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int cached, int match_missing,
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unsigned *dirty_submodule, struct diff_options *diffopt)
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{
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const unsigned char *sha1 = ce->sha1;
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unsigned int mode = ce->ce_mode;
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if (!cached && !ce_uptodate(ce)) {
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int changed;
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struct stat st;
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changed = check_removed(ce, &st);
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if (changed < 0)
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return -1;
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else if (changed) {
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if (match_missing) {
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*sha1p = sha1;
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*modep = mode;
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return 0;
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}
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return -1;
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}
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changed = match_stat_with_submodule(diffopt, ce, &st,
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0, dirty_submodule);
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if (changed) {
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mode = ce_mode_from_stat(ce, st.st_mode);
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sha1 = null_sha1;
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}
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}
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*sha1p = sha1;
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*modep = mode;
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return 0;
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}
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static void show_new_file(struct rev_info *revs,
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struct cache_entry *new,
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int cached, int match_missing)
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{
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const unsigned char *sha1;
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unsigned int mode;
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unsigned dirty_submodule = 0;
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/*
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* New file in the index: it might actually be different in
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* the working tree.
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*/
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if (get_stat_data(new, &sha1, &mode, cached, match_missing,
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&dirty_submodule, &revs->diffopt) < 0)
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return;
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diff_index_show_file(revs, "+", new, sha1, !is_null_sha1(sha1), mode, dirty_submodule);
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}
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static int show_modified(struct rev_info *revs,
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struct cache_entry *old,
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struct cache_entry *new,
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int report_missing,
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int cached, int match_missing)
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{
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unsigned int mode, oldmode;
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const unsigned char *sha1;
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unsigned dirty_submodule = 0;
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if (get_stat_data(new, &sha1, &mode, cached, match_missing,
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&dirty_submodule, &revs->diffopt) < 0) {
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if (report_missing)
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diff_index_show_file(revs, "-", old,
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old->sha1, 1, old->ce_mode, 0);
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return -1;
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}
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if (revs->combine_merges && !cached &&
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(hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
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struct combine_diff_path *p;
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int pathlen = ce_namelen(new);
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p = xmalloc(combine_diff_path_size(2, pathlen));
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p->path = (char *) &p->parent[2];
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p->next = NULL;
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p->len = pathlen;
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memcpy(p->path, new->name, pathlen);
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p->path[pathlen] = 0;
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p->mode = mode;
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hashclr(p->sha1);
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memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
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p->parent[0].status = DIFF_STATUS_MODIFIED;
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p->parent[0].mode = new->ce_mode;
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hashcpy(p->parent[0].sha1, new->sha1);
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p->parent[1].status = DIFF_STATUS_MODIFIED;
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p->parent[1].mode = old->ce_mode;
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hashcpy(p->parent[1].sha1, old->sha1);
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show_combined_diff(p, 2, revs->dense_combined_merges, revs);
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free(p);
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return 0;
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}
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oldmode = old->ce_mode;
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if (mode == oldmode && !hashcmp(sha1, old->sha1) && !dirty_submodule &&
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!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
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return 0;
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diff_change(&revs->diffopt, oldmode, mode,
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old->sha1, sha1, 1, !is_null_sha1(sha1),
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old->name, 0, dirty_submodule);
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return 0;
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}
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/*
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* This gets a mix of an existing index and a tree, one pathname entry
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* at a time. The index entry may be a single stage-0 one, but it could
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* also be multiple unmerged entries (in which case idx_pos/idx_nr will
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* give you the position and number of entries in the index).
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*/
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static void do_oneway_diff(struct unpack_trees_options *o,
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struct cache_entry *idx,
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struct cache_entry *tree)
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{
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struct rev_info *revs = o->unpack_data;
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int match_missing, cached;
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/* if the entry is not checked out, don't examine work tree */
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cached = o->index_only ||
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(idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
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/*
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* Backward compatibility wart - "diff-index -m" does
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* not mean "do not ignore merges", but "match_missing".
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*
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* But with the revision flag parsing, that's found in
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* "!revs->ignore_merges".
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*/
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match_missing = !revs->ignore_merges;
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if (cached && idx && ce_stage(idx)) {
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struct diff_filepair *pair;
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pair = diff_unmerge(&revs->diffopt, idx->name);
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if (tree)
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fill_filespec(pair->one, tree->sha1, 1, tree->ce_mode);
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return;
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}
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/*
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* Something added to the tree?
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*/
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if (!tree) {
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show_new_file(revs, idx, cached, match_missing);
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return;
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}
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/*
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* Something removed from the tree?
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*/
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if (!idx) {
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diff_index_show_file(revs, "-", tree, tree->sha1, 1, tree->ce_mode, 0);
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return;
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}
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/* Show difference between old and new */
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show_modified(revs, tree, idx, 1, cached, match_missing);
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}
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/*
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* The unpack_trees() interface is designed for merging, so
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* the different source entries are designed primarily for
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* the source trees, with the old index being really mainly
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* used for being replaced by the result.
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*
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* For diffing, the index is more important, and we only have a
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* single tree.
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*
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* We're supposed to advance o->pos to skip what we have already processed.
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*
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* This wrapper makes it all more readable, and takes care of all
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* the fairly complex unpack_trees() semantic requirements, including
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* the skipping, the path matching, the type conflict cases etc.
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*/
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static int oneway_diff(struct cache_entry **src, struct unpack_trees_options *o)
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{
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struct cache_entry *idx = src[0];
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struct cache_entry *tree = src[1];
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struct rev_info *revs = o->unpack_data;
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/*
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* Unpack-trees generates a DF/conflict entry if
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* there was a directory in the index and a tree
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* in the tree. From a diff standpoint, that's a
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* delete of the tree and a create of the file.
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*/
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if (tree == o->df_conflict_entry)
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tree = NULL;
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if (ce_path_match(idx ? idx : tree, &revs->prune_data)) {
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do_oneway_diff(o, idx, tree);
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if (diff_can_quit_early(&revs->diffopt)) {
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o->exiting_early = 1;
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return -1;
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}
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}
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return 0;
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}
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static int diff_cache(struct rev_info *revs,
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const unsigned char *tree_sha1,
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const char *tree_name,
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int cached)
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{
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struct tree *tree;
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struct tree_desc t;
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struct unpack_trees_options opts;
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tree = parse_tree_indirect(tree_sha1);
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if (!tree)
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return error("bad tree object %s",
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tree_name ? tree_name : sha1_to_hex(tree_sha1));
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memset(&opts, 0, sizeof(opts));
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opts.head_idx = 1;
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opts.index_only = cached;
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opts.diff_index_cached = (cached &&
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!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER));
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opts.merge = 1;
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opts.fn = oneway_diff;
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opts.unpack_data = revs;
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opts.src_index = &the_index;
|
|
opts.dst_index = NULL;
|
|
opts.pathspec = &revs->diffopt.pathspec;
|
|
opts.pathspec->recursive = 1;
|
|
opts.pathspec->max_depth = -1;
|
|
|
|
init_tree_desc(&t, tree->buffer, tree->size);
|
|
return unpack_trees(1, &t, &opts);
|
|
}
|
|
|
|
int run_diff_index(struct rev_info *revs, int cached)
|
|
{
|
|
struct object_array_entry *ent;
|
|
|
|
ent = revs->pending.objects;
|
|
if (diff_cache(revs, ent->item->sha1, ent->name, cached))
|
|
exit(128);
|
|
|
|
diff_set_mnemonic_prefix(&revs->diffopt, "c/", cached ? "i/" : "w/");
|
|
diffcore_fix_diff_index(&revs->diffopt);
|
|
diffcore_std(&revs->diffopt);
|
|
diff_flush(&revs->diffopt);
|
|
return 0;
|
|
}
|
|
|
|
int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
|
|
{
|
|
struct rev_info revs;
|
|
|
|
init_revisions(&revs, NULL);
|
|
init_pathspec(&revs.prune_data, opt->pathspec.raw);
|
|
revs.diffopt = *opt;
|
|
|
|
if (diff_cache(&revs, tree_sha1, NULL, 1))
|
|
exit(128);
|
|
return 0;
|
|
}
|
|
|
|
int index_differs_from(const char *def, int diff_flags)
|
|
{
|
|
struct rev_info rev;
|
|
struct setup_revision_opt opt;
|
|
|
|
init_revisions(&rev, NULL);
|
|
memset(&opt, 0, sizeof(opt));
|
|
opt.def = def;
|
|
setup_revisions(0, NULL, &rev, &opt);
|
|
DIFF_OPT_SET(&rev.diffopt, QUICK);
|
|
DIFF_OPT_SET(&rev.diffopt, EXIT_WITH_STATUS);
|
|
rev.diffopt.flags |= diff_flags;
|
|
run_diff_index(&rev, 1);
|
|
if (rev.pending.alloc)
|
|
free(rev.pending.objects);
|
|
return (DIFF_OPT_TST(&rev.diffopt, HAS_CHANGES) != 0);
|
|
}
|