diff options
Diffstat (limited to 'tree-diff.c')
| -rw-r--r-- | tree-diff.c | 332 |
1 files changed, 332 insertions, 0 deletions
diff --git a/tree-diff.c b/tree-diff.c new file mode 100644 index 0000000000..456660c7a2 --- /dev/null +++ b/tree-diff.c @@ -0,0 +1,332 @@ +/* + * Helper functions for tree diff generation + */ +#include "cache.h" +#include "diff.h" +#include "diffcore.h" +#include "tree.h" + +static void show_entry(struct diff_options *opt, const char *prefix, + struct tree_desc *desc, struct strbuf *base); + +static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, + struct strbuf *base, struct diff_options *opt) +{ + unsigned mode1, mode2; + const char *path1, *path2; + const unsigned char *sha1, *sha2; + int cmp, pathlen1, pathlen2; + int old_baselen = base->len; + + sha1 = tree_entry_extract(t1, &path1, &mode1); + sha2 = tree_entry_extract(t2, &path2, &mode2); + + pathlen1 = tree_entry_len(&t1->entry); + pathlen2 = tree_entry_len(&t2->entry); + cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2); + if (cmp < 0) { + show_entry(opt, "-", t1, base); + return -1; + } + if (cmp > 0) { + show_entry(opt, "+", t2, base); + 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); + show_entry(opt, "+", t2, base); + return 0; + } + + strbuf_add(base, path1, pathlen1); + if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode1)) { + if (DIFF_OPT_TST(opt, TREE_IN_RECURSIVE)) { + opt->change(opt, mode1, mode2, + sha1, sha2, 1, 1, base->buf, 0, 0); + } + strbuf_addch(base, '/'); + diff_tree_sha1(sha1, sha2, base->buf, opt); + } else { + opt->change(opt, mode1, mode2, sha1, sha2, 1, 1, base->buf, 0, 0); + } + strbuf_setlen(base, old_baselen); + return 0; +} + +/* A whole sub-tree went away or appeared */ +static void show_tree(struct diff_options *opt, const char *prefix, + struct tree_desc *desc, struct strbuf *base) +{ + enum interesting match = entry_not_interesting; + for (; desc->size; update_tree_entry(desc)) { + if (match != all_entries_interesting) { + match = tree_entry_interesting(&desc->entry, base, 0, + &opt->pathspec); + if (match == all_entries_not_interesting) + break; + if (match == entry_not_interesting) + continue; + } + show_entry(opt, prefix, desc, base); + } +} + +/* A file entry went away or appeared */ +static void show_entry(struct diff_options *opt, const char *prefix, + struct tree_desc *desc, struct strbuf *base) +{ + unsigned mode; + const char *path; + const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode); + int pathlen = tree_entry_len(&desc->entry); + int old_baselen = base->len; + + strbuf_add(base, path, pathlen); + if (DIFF_OPT_TST(opt, RECURSIVE) && S_ISDIR(mode)) { + enum object_type type; + 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)) + opt->add_remove(opt, *prefix, mode, sha1, 1, base->buf, 0); + + strbuf_addch(base, '/'); + + init_tree_desc(&inner, tree, size); + show_tree(opt, prefix, &inner, base); + free(tree); + } else + opt->add_remove(opt, prefix[0], mode, sha1, 1, base->buf, 0); + + strbuf_setlen(base, old_baselen); +} + +static void skip_uninteresting(struct tree_desc *t, struct strbuf *base, + struct diff_options *opt, + enum interesting *match) +{ + while (t->size) { + *match = tree_entry_interesting(&t->entry, base, 0, &opt->pathspec); + if (*match) { + if (*match == all_entries_not_interesting) + t->size = 0; + break; + } + update_tree_entry(t); + } +} + +int diff_tree(struct tree_desc *t1, struct tree_desc *t2, + const char *base_str, struct diff_options *opt) +{ + struct strbuf base; + int baselen = strlen(base_str); + enum interesting t1_match = entry_not_interesting; + enum interesting t2_match = entry_not_interesting; + + /* Enable recursion indefinitely */ + opt->pathspec.recursive = DIFF_OPT_TST(opt, RECURSIVE); + + strbuf_init(&base, PATH_MAX); + strbuf_add(&base, base_str, baselen); + + for (;;) { + if (diff_can_quit_early(opt)) + break; + if (opt->pathspec.nr) { + skip_uninteresting(t1, &base, opt, &t1_match); + skip_uninteresting(t2, &base, opt, &t2_match); + } + if (!t1->size) { + if (!t2->size) + break; + show_entry(opt, "+", t2, &base); + update_tree_entry(t2); + continue; + } + if (!t2->size) { + show_entry(opt, "-", t1, &base); + update_tree_entry(t1); + continue; + } + switch (compare_tree_entry(t1, t2, &base, 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"); + } + + strbuf_release(&base); + 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; + int i; + + /* + * follow-rename code is very specific, we need exactly one + * path. Magic that matches more than one path is not + * supported. + */ + GUARD_PATHSPEC(&opt->pathspec, PATHSPEC_FROMTOP | PATHSPEC_LITERAL); +#if 0 + /* + * We should reject wildcards as well. Unfortunately we + * haven't got a reliable way to detect that 'foo\*bar' in + * fact has no wildcards. nowildcard_len is merely a hint for + * optimization. Let it slip for now until wildmatch is taught + * about dry-run mode and returns wildcard info. + */ + if (opt->pathspec.has_wildcard) + die("BUG:%s:%d: wildcards are not supported", + __FILE__, __LINE__); +#endif + + /* 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_OPT_SET(&diff_opts, FIND_COPIES_HARDER); + diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT; + diff_opts.single_follow = opt->pathspec.items[0].match; + diff_opts.break_opt = opt->break_opt; + diff_opts.rename_score = opt->rename_score; + diff_setup_done(&diff_opts); + diff_tree(t1, t2, base, &diff_opts); + diffcore_std(&diff_opts); + free_pathspec(&diff_opts.pathspec); + + /* Go through the new set of filepairing, and see if we find a more interesting one */ + opt->found_follow = 0; + 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->pathspec.items[0].match)) { + const char *path[2]; + + /* Switch the file-pairs around */ + q->queue[i] = choice; + choice = p; + + /* Update the path we use from now on.. */ + path[0] = p->one->path; + path[1] = NULL; + free_pathspec(&opt->pathspec); + parse_pathspec(&opt->pathspec, + PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL, + PATHSPEC_LITERAL_PATH, "", path); + + /* + * The caller expects us to return a set of vanilla + * filepairs to let a later call to diffcore_std() + * it makes to sort the renames out (among other + * things), but we already have found renames + * ourselves; signal diffcore_std() not to muck with + * rename information. + */ + opt->found_follow = 1; + 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 (!*base && 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; +} |