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-rw-r--r--tree-diff.c475
1 files changed, 475 insertions, 0 deletions
diff --git a/tree-diff.c b/tree-diff.c
new file mode 100644
index 0000000000..fe9f52c479
--- /dev/null
+++ b/tree-diff.c
@@ -0,0 +1,475 @@
+/*
+ * Helper functions for tree diff generation
+ */
+#include "cache.h"
+#include "diff.h"
+#include "diffcore.h"
+#include "tree.h"
+
+static char *malloc_base(const char *base, int baselen, const char *path, int pathlen)
+{
+ char *newbase = xmalloc(baselen + pathlen + 2);
+ memcpy(newbase, base, baselen);
+ memcpy(newbase + baselen, path, pathlen);
+ memcpy(newbase + baselen + pathlen, "/", 2);
+ return newbase;
+}
+
+static char *malloc_fullname(const char *base, int baselen, const char *path, int pathlen)
+{
+ char *fullname = xmalloc(baselen + pathlen + 1);
+ memcpy(fullname, base, baselen);
+ memcpy(fullname + baselen, path, pathlen);
+ fullname[baselen + pathlen] = 0;
+ return fullname;
+}
+
+static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
+ const char *base, int baselen);
+
+static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, int baselen, struct diff_options *opt)
+{
+ unsigned mode1, mode2;
+ const char *path1, *path2;
+ const unsigned char *sha1, *sha2;
+ int cmp, pathlen1, pathlen2;
+ char *fullname;
+
+ sha1 = tree_entry_extract(t1, &path1, &mode1);
+ sha2 = tree_entry_extract(t2, &path2, &mode2);
+
+ pathlen1 = tree_entry_len(path1, sha1);
+ pathlen2 = tree_entry_len(path2, sha2);
+ cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
+ if (cmp < 0) {
+ show_entry(opt, "-", t1, base, baselen);
+ return -1;
+ }
+ if (cmp > 0) {
+ show_entry(opt, "+", t2, base, baselen);
+ return 1;
+ }
+ if (!DIFF_OPT_TST(opt, FIND_COPIES_HARDER) && !hashcmp(sha1, sha2) && mode1 == mode2)
+ return 0;
+
+ /*
+ * If the filemode has changed to/from a directory from/to a regular
+ * file, we need to consider it a remove and an add.
+ */
+ if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
+ show_entry(opt, "-", t1, base, baselen);
+ show_entry(opt, "+", t2, base, baselen);
+ return 0;
+ }
+
+ if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode1)) {
+ int retval;
+ char *newbase = malloc_base(base, baselen, path1, pathlen1);
+ if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
+ newbase[baselen + pathlen1] = 0;
+ opt->change(opt, mode1, mode2,
+ sha1, sha2, newbase, 0, 0);
+ newbase[baselen + pathlen1] = '/';
+ }
+ retval = diff_tree_sha1(sha1, sha2, newbase, opt);
+ free(newbase);
+ return retval;
+ }
+
+ fullname = malloc_fullname(base, baselen, path1, pathlen1);
+ opt->change(opt, mode1, mode2, sha1, sha2, fullname, 0, 0);
+ free(fullname);
+ return 0;
+}
+
+/*
+ * Is a tree entry interesting given the pathspec we have?
+ *
+ * Return:
+ * - 2 for "yes, and all subsequent entries will be"
+ * - 1 for yes
+ * - zero for no
+ * - negative for "no, and no subsequent entries will be either"
+ */
+static int tree_entry_interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt)
+{
+ const char *path;
+ const unsigned char *sha1;
+ unsigned mode;
+ int i;
+ int pathlen;
+ int never_interesting = -1;
+
+ if (!opt->nr_paths)
+ return 1;
+
+ sha1 = tree_entry_extract(desc, &path, &mode);
+
+ pathlen = tree_entry_len(path, sha1);
+
+ for (i = 0; i < opt->nr_paths; i++) {
+ const char *match = opt->paths[i];
+ int matchlen = opt->pathlens[i];
+ int m = -1; /* signals that we haven't called strncmp() */
+
+ if (baselen >= matchlen) {
+ /* If it doesn't match, move along... */
+ if (strncmp(base, match, matchlen))
+ continue;
+
+ /*
+ * If the base is a subdirectory of a path which
+ * was specified, all of them are interesting.
+ */
+ if (!matchlen ||
+ base[matchlen] == '/' ||
+ match[matchlen - 1] == '/')
+ return 2;
+
+ /* Just a random prefix match */
+ continue;
+ }
+
+ /* Does the base match? */
+ if (strncmp(base, match, baselen))
+ continue;
+
+ match += baselen;
+ matchlen -= baselen;
+
+ if (never_interesting) {
+ /*
+ * We have not seen any match that sorts later
+ * than the current path.
+ */
+
+ /*
+ * Does match sort strictly earlier than path
+ * with their common parts?
+ */
+ m = strncmp(match, path,
+ (matchlen < pathlen) ? matchlen : pathlen);
+ if (m < 0)
+ continue;
+
+ /*
+ * If we come here even once, that means there is at
+ * least one pathspec that would sort equal to or
+ * later than the path we are currently looking at.
+ * In other words, if we have never reached this point
+ * after iterating all pathspecs, it means all
+ * pathspecs are either outside of base, or inside the
+ * base but sorts strictly earlier than the current
+ * one. In either case, they will never match the
+ * subsequent entries. In such a case, we initialized
+ * the variable to -1 and that is what will be
+ * returned, allowing the caller to terminate early.
+ */
+ never_interesting = 0;
+ }
+
+ if (pathlen > matchlen)
+ continue;
+
+ if (matchlen > pathlen) {
+ if (match[pathlen] != '/')
+ continue;
+ if (!S_ISDIR(mode))
+ continue;
+ }
+
+ if (m == -1)
+ /*
+ * we cheated and did not do strncmp(), so we do
+ * that here.
+ */
+ m = strncmp(match, path, pathlen);
+
+ /*
+ * If common part matched earlier then it is a hit,
+ * because we rejected the case where path is not a
+ * leading directory and is shorter than match.
+ */
+ if (!m)
+ return 1;
+ }
+ return never_interesting; /* No matches */
+}
+
+/* A whole sub-tree went away or appeared */
+static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base, int baselen)
+{
+ int all_interesting = 0;
+ while (desc->size) {
+ int show;
+
+ if (all_interesting)
+ show = 1;
+ else {
+ show = tree_entry_interesting(desc, base, baselen,
+ opt);
+ if (show == 2)
+ all_interesting = 1;
+ }
+ if (show < 0)
+ break;
+ if (show)
+ show_entry(opt, prefix, desc, base, baselen);
+ update_tree_entry(desc);
+ }
+}
+
+/* A file entry went away or appeared */
+static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
+ const char *base, int baselen)
+{
+ unsigned mode;
+ const char *path;
+ const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
+ int pathlen = tree_entry_len(path, sha1);
+
+ if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) {
+ enum object_type type;
+ char *newbase = malloc_base(base, baselen, path, pathlen);
+ struct tree_desc inner;
+ void *tree;
+ unsigned long size;
+
+ tree = read_sha1_file(sha1, &type, &size);
+ if (!tree || type != OBJ_TREE)
+ die("corrupt tree sha %s", sha1_to_hex(sha1));
+
+ if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) {
+ newbase[baselen + pathlen] = 0;
+ opt->add_remove(opt, *prefix, mode, sha1, newbase, 0);
+ newbase[baselen + pathlen] = '/';
+ }
+
+ init_tree_desc(&inner, tree, size);
+ show_tree(opt, prefix, &inner, newbase, baselen + 1 + pathlen);
+
+ free(tree);
+ free(newbase);
+ } else {
+ char *fullname = malloc_fullname(base, baselen, path, pathlen);
+ opt->add_remove(opt, prefix[0], mode, sha1, fullname, 0);
+ free(fullname);
+ }
+}
+
+static void skip_uninteresting(struct tree_desc *t, const char *base, int baselen, struct diff_options *opt)
+{
+ int all_interesting = 0;
+ while (t->size) {
+ int show;
+
+ if (all_interesting)
+ show = 1;
+ else {
+ show = tree_entry_interesting(t, base, baselen, opt);
+ if (show == 2)
+ all_interesting = 1;
+ }
+ if (!show) {
+ update_tree_entry(t);
+ continue;
+ }
+ /* Skip it all? */
+ if (show < 0)
+ t->size = 0;
+ return;
+ }
+}
+
+int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
+{
+ int baselen = strlen(base);
+
+ for (;;) {
+ if (DIFF_OPT_TST(opt, QUICK) &&
+ DIFF_OPT_TST(opt, HAS_CHANGES))
+ break;
+ if (opt->nr_paths) {
+ skip_uninteresting(t1, base, baselen, opt);
+ skip_uninteresting(t2, base, baselen, opt);
+ }
+ if (!t1->size) {
+ if (!t2->size)
+ break;
+ show_entry(opt, "+", t2, base, baselen);
+ update_tree_entry(t2);
+ continue;
+ }
+ if (!t2->size) {
+ show_entry(opt, "-", t1, base, baselen);
+ update_tree_entry(t1);
+ continue;
+ }
+ switch (compare_tree_entry(t1, t2, base, baselen, opt)) {
+ case -1:
+ update_tree_entry(t1);
+ continue;
+ case 0:
+ update_tree_entry(t1);
+ /* Fallthrough */
+ case 1:
+ update_tree_entry(t2);
+ continue;
+ }
+ die("git diff-tree: internal error");
+ }
+ return 0;
+}
+
+/*
+ * Does it look like the resulting diff might be due to a rename?
+ * - single entry
+ * - not a valid previous file
+ */
+static inline int diff_might_be_rename(void)
+{
+ return diff_queued_diff.nr == 1 &&
+ !DIFF_FILE_VALID(diff_queued_diff.queue[0]->one);
+}
+
+static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
+{
+ struct diff_options diff_opts;
+ struct diff_queue_struct *q = &diff_queued_diff;
+ struct diff_filepair *choice;
+ const char *paths[1];
+ int i;
+
+ /* Remove the file creation entry from the diff queue, and remember it */
+ choice = q->queue[0];
+ q->nr = 0;
+
+ diff_setup(&diff_opts);
+ DIFF_OPT_SET(&diff_opts, RECURSIVE);
+ diff_opts.detect_rename = DIFF_DETECT_RENAME;
+ diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
+ diff_opts.single_follow = opt->paths[0];
+ diff_opts.break_opt = opt->break_opt;
+ paths[0] = NULL;
+ diff_tree_setup_paths(paths, &diff_opts);
+ if (diff_setup_done(&diff_opts) < 0)
+ die("unable to set up diff options to follow renames");
+ diff_tree(t1, t2, base, &diff_opts);
+ diffcore_std(&diff_opts);
+ diff_tree_release_paths(&diff_opts);
+
+ /* Go through the new set of filepairing, and see if we find a more interesting one */
+ for (i = 0; i < q->nr; i++) {
+ struct diff_filepair *p = q->queue[i];
+
+ /*
+ * Found a source? Not only do we use that for the new
+ * diff_queued_diff, we will also use that as the path in
+ * the future!
+ */
+ if ((p->status == 'R' || p->status == 'C') && !strcmp(p->two->path, opt->paths[0])) {
+ /* Switch the file-pairs around */
+ q->queue[i] = choice;
+ choice = p;
+
+ /* Update the path we use from now on.. */
+ diff_tree_release_paths(opt);
+ opt->paths[0] = xstrdup(p->one->path);
+ diff_tree_setup_paths(opt->paths, opt);
+ break;
+ }
+ }
+
+ /*
+ * Then, discard all the non-relevant file pairs...
+ */
+ for (i = 0; i < q->nr; i++) {
+ struct diff_filepair *p = q->queue[i];
+ diff_free_filepair(p);
+ }
+
+ /*
+ * .. and re-instate the one we want (which might be either the
+ * original one, or the rename/copy we found)
+ */
+ q->queue[0] = choice;
+ q->nr = 1;
+}
+
+int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
+{
+ void *tree1, *tree2;
+ struct tree_desc t1, t2;
+ unsigned long size1, size2;
+ int retval;
+
+ tree1 = read_object_with_reference(old, tree_type, &size1, NULL);
+ if (!tree1)
+ die("unable to read source tree (%s)", sha1_to_hex(old));
+ tree2 = read_object_with_reference(new, tree_type, &size2, NULL);
+ if (!tree2)
+ die("unable to read destination tree (%s)", sha1_to_hex(new));
+ init_tree_desc(&t1, tree1, size1);
+ init_tree_desc(&t2, tree2, size2);
+ retval = diff_tree(&t1, &t2, base, opt);
+ if (DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
+ init_tree_desc(&t1, tree1, size1);
+ init_tree_desc(&t2, tree2, size2);
+ try_to_follow_renames(&t1, &t2, base, opt);
+ }
+ free(tree1);
+ free(tree2);
+ return retval;
+}
+
+int diff_root_tree_sha1(const unsigned char *new, const char *base, struct diff_options *opt)
+{
+ int retval;
+ void *tree;
+ unsigned long size;
+ struct tree_desc empty, real;
+
+ tree = read_object_with_reference(new, tree_type, &size, NULL);
+ if (!tree)
+ die("unable to read root tree (%s)", sha1_to_hex(new));
+ init_tree_desc(&real, tree, size);
+
+ init_tree_desc(&empty, "", 0);
+ retval = diff_tree(&empty, &real, base, opt);
+ free(tree);
+ return retval;
+}
+
+static int count_paths(const char **paths)
+{
+ int i = 0;
+ while (*paths++)
+ i++;
+ return i;
+}
+
+void diff_tree_release_paths(struct diff_options *opt)
+{
+ free(opt->pathlens);
+}
+
+void diff_tree_setup_paths(const char **p, struct diff_options *opt)
+{
+ opt->nr_paths = 0;
+ opt->pathlens = NULL;
+ opt->paths = NULL;
+
+ if (p) {
+ int i;
+
+ opt->paths = p;
+ opt->nr_paths = count_paths(p);
+ if (opt->nr_paths == 0) {
+ opt->pathlens = NULL;
+ return;
+ }
+ opt->pathlens = xmalloc(opt->nr_paths * sizeof(int));
+ for (i=0; i < opt->nr_paths; i++)
+ opt->pathlens[i] = strlen(p[i]);
+ }
+}