1 files changed, 536 insertions, 0 deletions

diff --git a/diff-lib.c b/diff-lib.c
new file mode 100644
index 0000000..8b8978ae
--- /dev/null
+++ b/diff-lib.c
@@ -0,0 +1,536 @@
+/*
+ * Copyright (C) 2005 Junio C Hamano
+ */
+#include "cache.h"
+#include "quote.h"
+#include "commit.h"
+#include "diff.h"
+#include "diffcore.h"
+#include "revision.h"
+#include "cache-tree.h"
+#include "unpack-trees.h"
+#include "refs.h"
+#include "submodule.h"
+
+/*
+ * diff-files
+ */
+
+/*
+ * Has the work tree entity been removed?
+ *
+ * Return 1 if it was removed from the work tree, 0 if an entity to be
+ * compared with the cache entry ce still exists (the latter includes
+ * the case where a directory that is not a submodule repository
+ * exists for ce that is a submodule -- it is a submodule that is not
+ * checked out).  Return negative for an error.
+ */
+static int check_removed(const struct cache_entry *ce, struct stat *st)
+{
+	if (lstat(ce->name, st) < 0) {
+		if (errno != ENOENT && errno != ENOTDIR)
+			return -1;
+		return 1;
+	}
+	if (has_symlink_leading_path(ce->name, ce_namelen(ce)))
+		return 1;
+	if (S_ISDIR(st->st_mode)) {
+		unsigned char sub[20];
+
+		/*
+		 * If ce is already a gitlink, we can have a plain
+		 * directory (i.e. the submodule is not checked out),
+		 * or a checked out submodule.  Either case this is not
+		 * a case where something was removed from the work tree,
+		 * so we will return 0.
+		 *
+		 * Otherwise, if the directory is not a submodule
+		 * repository, that means ce which was a blob turned into
+		 * a directory --- the blob was removed!
+		 */
+		if (!S_ISGITLINK(ce->ce_mode) &&
+		    resolve_gitlink_ref(ce->name, "HEAD", sub))
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * Has a file changed or has a submodule new commits or a dirty work tree?
+ *
+ * Return 1 when changes are detected, 0 otherwise. If the DIRTY_SUBMODULES
+ * option is set, the caller does not only want to know if a submodule is
+ * modified at all but wants to know all the conditions that are met (new
+ * commits, untracked content and/or modified content).
+ */
+static int match_stat_with_submodule(struct diff_options *diffopt,
+				      struct cache_entry *ce, struct stat *st,
+				      unsigned ce_option, unsigned *dirty_submodule)
+{
+	int changed = ce_match_stat(ce, st, ce_option);
+	if (S_ISGITLINK(ce->ce_mode)
+	    && !DIFF_OPT_TST(diffopt, IGNORE_SUBMODULES)
+	    && !DIFF_OPT_TST(diffopt, IGNORE_DIRTY_SUBMODULES)
+	    && (!changed || DIFF_OPT_TST(diffopt, DIRTY_SUBMODULES))) {
+		*dirty_submodule = is_submodule_modified(ce->name, DIFF_OPT_TST(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES));
+	}
+	return changed;
+}
+
+int run_diff_files(struct rev_info *revs, unsigned int option)
+{
+	int entries, i;
+	int diff_unmerged_stage = revs->max_count;
+	int silent_on_removed = option & DIFF_SILENT_ON_REMOVED;
+	unsigned ce_option = ((option & DIFF_RACY_IS_MODIFIED)
+			      ? CE_MATCH_RACY_IS_DIRTY : 0);
+
+	diff_set_mnemonic_prefix(&revs->diffopt, "i/", "w/");
+
+	if (diff_unmerged_stage < 0)
+		diff_unmerged_stage = 2;
+	entries = active_nr;
+	for (i = 0; i < entries; i++) {
+		struct stat st;
+		unsigned int oldmode, newmode;
+		struct cache_entry *ce = active_cache[i];
+		int changed;
+		unsigned dirty_submodule = 0;
+
+		if (DIFF_OPT_TST(&revs->diffopt, QUICK) &&
+			DIFF_OPT_TST(&revs->diffopt, HAS_CHANGES))
+			break;
+
+		if (!ce_path_match(ce, revs->prune_data))
+			continue;
+
+		if (ce_stage(ce)) {
+			struct combine_diff_path *dpath;
+			int num_compare_stages = 0;
+			size_t path_len;
+
+			path_len = ce_namelen(ce);
+
+			dpath = xmalloc(combine_diff_path_size(5, path_len));
+			dpath->path = (char *) &(dpath->parent[5]);
+
+			dpath->next = NULL;
+			dpath->len = path_len;
+			memcpy(dpath->path, ce->name, path_len);
+			dpath->path[path_len] = '\0';
+			hashclr(dpath->sha1);
+			memset(&(dpath->parent[0]), 0,
+			       sizeof(struct combine_diff_parent)*5);
+
+			changed = check_removed(ce, &st);
+			if (!changed)
+				dpath->mode = ce_mode_from_stat(ce, st.st_mode);
+			else {
+				if (changed < 0) {
+					perror(ce->name);
+					continue;
+				}
+				if (silent_on_removed)
+					continue;
+			}
+
+			while (i < entries) {
+				struct cache_entry *nce = active_cache[i];
+				int stage;
+
+				if (strcmp(ce->name, nce->name))
+					break;
+
+				/* Stage #2 (ours) is the first parent,
+				 * stage #3 (theirs) is the second.
+				 */
+				stage = ce_stage(nce);
+				if (2 <= stage) {
+					int mode = nce->ce_mode;
+					num_compare_stages++;
+					hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
+					dpath->parent[stage-2].mode = ce_mode_from_stat(nce, mode);
+					dpath->parent[stage-2].status =
+						DIFF_STATUS_MODIFIED;
+				}
+
+				/* diff against the proper unmerged stage */
+				if (stage == diff_unmerged_stage)
+					ce = nce;
+				i++;
+			}
+			/*
+			 * Compensate for loop update
+			 */
+			i--;
+
+			if (revs->combine_merges && num_compare_stages == 2) {
+				show_combined_diff(dpath, 2,
+						   revs->dense_combined_merges,
+						   revs);
+				free(dpath);
+				continue;
+			}
+			free(dpath);
+			dpath = NULL;
+
+			/*
+			 * Show the diff for the 'ce' if we found the one
+			 * from the desired stage.
+			 */
+			diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
+			if (ce_stage(ce) != diff_unmerged_stage)
+				continue;
+		}
+
+		if (ce_uptodate(ce) || ce_skip_worktree(ce))
+			continue;
+
+		/* If CE_VALID is set, don't look at workdir for file removal */
+		changed = (ce->ce_flags & CE_VALID) ? 0 : check_removed(ce, &st);
+		if (changed) {
+			if (changed < 0) {
+				perror(ce->name);
+				continue;
+			}
+			if (silent_on_removed)
+				continue;
+			diff_addremove(&revs->diffopt, '-', ce->ce_mode,
+				       ce->sha1, ce->name, 0);
+			continue;
+		}
+		changed = match_stat_with_submodule(&revs->diffopt, ce, &st,
+						    ce_option, &dirty_submodule);
+		if (!changed && !dirty_submodule) {
+			ce_mark_uptodate(ce);
+			if (!DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
+				continue;
+		}
+		oldmode = ce->ce_mode;
+		newmode = ce_mode_from_stat(ce, st.st_mode);
+		diff_change(&revs->diffopt, oldmode, newmode,
+			    ce->sha1, (changed ? null_sha1 : ce->sha1),
+			    ce->name, 0, dirty_submodule);
+
+	}
+	diffcore_std(&revs->diffopt);
+	diff_flush(&revs->diffopt);
+	return 0;
+}
+
+/*
+ * diff-index
+ */
+
+/* A file entry went away or appeared */
+static void diff_index_show_file(struct rev_info *revs,
+				 const char *prefix,
+				 struct cache_entry *ce,
+				 const unsigned char *sha1, unsigned int mode,
+				 unsigned dirty_submodule)
+{
+	diff_addremove(&revs->diffopt, prefix[0], mode,
+		       sha1, ce->name, dirty_submodule);
+}
+
+static int get_stat_data(struct cache_entry *ce,
+			 const unsigned char **sha1p,
+			 unsigned int *modep,
+			 int cached, int match_missing,
+			 unsigned *dirty_submodule, struct diff_options *diffopt)
+{
+	const unsigned char *sha1 = ce->sha1;
+	unsigned int mode = ce->ce_mode;
+
+	if (!cached && !ce_uptodate(ce)) {
+		int changed;
+		struct stat st;
+		changed = check_removed(ce, &st);
+		if (changed < 0)
+			return -1;
+		else if (changed) {
+			if (match_missing) {
+				*sha1p = sha1;
+				*modep = mode;
+				return 0;
+			}
+			return -1;
+		}
+		changed = match_stat_with_submodule(diffopt, ce, &st,
+						    0, dirty_submodule);
+		if (changed) {
+			mode = ce_mode_from_stat(ce, st.st_mode);
+			sha1 = null_sha1;
+		}
+	}
+
+	*sha1p = sha1;
+	*modep = mode;
+	return 0;
+}
+
+static void show_new_file(struct rev_info *revs,
+			  struct cache_entry *new,
+			  int cached, int match_missing)
+{
+	const unsigned char *sha1;
+	unsigned int mode;
+	unsigned dirty_submodule = 0;
+
+	/*
+	 * New file in the index: it might actually be different in
+	 * the working copy.
+	 */
+	if (get_stat_data(new, &sha1, &mode, cached, match_missing,
+	    &dirty_submodule, &revs->diffopt) < 0)
+		return;
+
+	diff_index_show_file(revs, "+", new, sha1, mode, dirty_submodule);
+}
+
+static int show_modified(struct rev_info *revs,
+			 struct cache_entry *old,
+			 struct cache_entry *new,
+			 int report_missing,
+			 int cached, int match_missing)
+{
+	unsigned int mode, oldmode;
+	const unsigned char *sha1;
+	unsigned dirty_submodule = 0;
+
+	if (get_stat_data(new, &sha1, &mode, cached, match_missing,
+			  &dirty_submodule, &revs->diffopt) < 0) {
+		if (report_missing)
+			diff_index_show_file(revs, "-", old,
+					     old->sha1, old->ce_mode, 0);
+		return -1;
+	}
+
+	if (revs->combine_merges && !cached &&
+	    (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
+		struct combine_diff_path *p;
+		int pathlen = ce_namelen(new);
+
+		p = xmalloc(combine_diff_path_size(2, pathlen));
+		p->path = (char *) &p->parent[2];
+		p->next = NULL;
+		p->len = pathlen;
+		memcpy(p->path, new->name, pathlen);
+		p->path[pathlen] = 0;
+		p->mode = mode;
+		hashclr(p->sha1);
+		memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
+		p->parent[0].status = DIFF_STATUS_MODIFIED;
+		p->parent[0].mode = new->ce_mode;
+		hashcpy(p->parent[0].sha1, new->sha1);
+		p->parent[1].status = DIFF_STATUS_MODIFIED;
+		p->parent[1].mode = old->ce_mode;
+		hashcpy(p->parent[1].sha1, old->sha1);
+		show_combined_diff(p, 2, revs->dense_combined_merges, revs);
+		free(p);
+		return 0;
+	}
+
+	oldmode = old->ce_mode;
+	if (mode == oldmode && !hashcmp(sha1, old->sha1) && !dirty_submodule &&
+	    !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER))
+		return 0;
+
+	diff_change(&revs->diffopt, oldmode, mode,
+		    old->sha1, sha1, old->name, 0, dirty_submodule);
+	return 0;
+}
+
+/*
+ * This gets a mix of an existing index and a tree, one pathname entry
+ * at a time. The index entry may be a single stage-0 one, but it could
+ * also be multiple unmerged entries (in which case idx_pos/idx_nr will
+ * give you the position and number of entries in the index).
+ */
+static void do_oneway_diff(struct unpack_trees_options *o,
+	struct cache_entry *idx,
+	struct cache_entry *tree)
+{
+	struct rev_info *revs = o->unpack_data;
+	int match_missing, cached;
+
+	/* if the entry is not checked out, don't examine work tree */
+	cached = o->index_only ||
+		(idx && ((idx->ce_flags & CE_VALID) || ce_skip_worktree(idx)));
+	/*
+	 * Backward compatibility wart - "diff-index -m" does
+	 * not mean "do not ignore merges", but "match_missing".
+	 *
+	 * But with the revision flag parsing, that's found in
+	 * "!revs->ignore_merges".
+	 */
+	match_missing = !revs->ignore_merges;
+
+	if (cached && idx && ce_stage(idx)) {
+		diff_unmerge(&revs->diffopt, idx->name, idx->ce_mode,
+			     idx->sha1);
+		return;
+	}
+
+	/*
+	 * Something added to the tree?
+	 */
+	if (!tree) {
+		show_new_file(revs, idx, cached, match_missing);
+		return;
+	}
+
+	/*
+	 * Something removed from the tree?
+	 */
+	if (!idx) {
+		diff_index_show_file(revs, "-", tree, tree->sha1, tree->ce_mode, 0);
+		return;
+	}
+
+	/* Show difference between old and new */
+	show_modified(revs, tree, idx, 1, cached, match_missing);
+}
+
+/*
+ * The unpack_trees() interface is designed for merging, so
+ * the different source entries are designed primarily for
+ * the source trees, with the old index being really mainly
+ * used for being replaced by the result.
+ *
+ * For diffing, the index is more important, and we only have a
+ * single tree.
+ *
+ * We're supposed to advance o->pos to skip what we have already processed.
+ *
+ * This wrapper makes it all more readable, and takes care of all
+ * the fairly complex unpack_trees() semantic requirements, including
+ * the skipping, the path matching, the type conflict cases etc.
+ */
+static int oneway_diff(struct cache_entry **src, struct unpack_trees_options *o)
+{
+	struct cache_entry *idx = src[0];
+	struct cache_entry *tree = src[1];
+	struct rev_info *revs = o->unpack_data;
+
+	/*
+	 * Unpack-trees generates a DF/conflict entry if
+	 * there was a directory in the index and a tree
+	 * in the tree. From a diff standpoint, that's a
+	 * delete of the tree and a create of the file.
+	 */
+	if (tree == o->df_conflict_entry)
+		tree = NULL;
+
+	if (ce_path_match(idx ? idx : tree, revs->prune_data))
+		do_oneway_diff(o, idx, tree);
+
+	return 0;
+}
+
+int run_diff_index(struct rev_info *revs, int cached)
+{
+	struct object *ent;
+	struct tree *tree;
+	const char *tree_name;
+	struct unpack_trees_options opts;
+	struct tree_desc t;
+
+	ent = revs->pending.objects[0].item;
+	tree_name = revs->pending.objects[0].name;
+	tree = parse_tree_indirect(ent->sha1);
+	if (!tree)
+		return error("bad tree object %s", tree_name);
+
+	memset(&opts, 0, sizeof(opts));
+	opts.head_idx = 1;
+	opts.index_only = cached;
+	opts.diff_index_cached = (cached &&
+				  !DIFF_OPT_TST(&revs->diffopt, FIND_COPIES_HARDER));
+	opts.merge = 1;
+	opts.fn = oneway_diff;
+	opts.unpack_data = revs;
+	opts.src_index = &the_index;
+	opts.dst_index = NULL;
+
+	init_tree_desc(&t, tree->buffer, tree->size);
+	if (unpack_trees(1, &t, &opts))
+		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 tree *tree;
+	struct rev_info revs;
+	int i;
+	struct cache_entry **dst;
+	struct cache_entry *last = NULL;
+	struct unpack_trees_options opts;
+	struct tree_desc t;
+
+	/*
+	 * This is used by git-blame to run diff-cache internally;
+	 * it potentially needs to repeatedly run this, so we will
+	 * start by removing the higher order entries the last round
+	 * left behind.
+	 */
+	dst = active_cache;
+	for (i = 0; i < active_nr; i++) {
+		struct cache_entry *ce = active_cache[i];
+		if (ce_stage(ce)) {
+			if (last && !strcmp(ce->name, last->name))
+				continue;
+			cache_tree_invalidate_path(active_cache_tree,
+						   ce->name);
+			last = ce;
+			ce->ce_flags |= CE_REMOVE;
+		}
+		*dst++ = ce;
+	}
+	active_nr = dst - active_cache;
+
+	init_revisions(&revs, NULL);
+	revs.prune_data = opt->paths;
+	tree = parse_tree_indirect(tree_sha1);
+	if (!tree)
+		die("bad tree object %s", sha1_to_hex(tree_sha1));
+
+	memset(&opts, 0, sizeof(opts));
+	opts.head_idx = 1;
+	opts.index_only = 1;
+	opts.diff_index_cached = !DIFF_OPT_TST(opt, FIND_COPIES_HARDER);
+	opts.merge = 1;
+	opts.fn = oneway_diff;
+	opts.unpack_data = &revs;
+	opts.src_index = &the_index;
+	opts.dst_index = &the_index;
+
+	init_tree_desc(&t, tree->buffer, tree->size);
+	if (unpack_trees(1, &t, &opts))
+		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);
+}