diff options
Diffstat (limited to 'tree-diff.c')
| -rw-r--r-- | tree-diff.c | 475 |
1 files changed, 475 insertions, 0 deletions
diff --git a/tree-diff.c b/tree-diff.c new file mode 100644 index 0000000..1fb3e94 --- /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_OPT_SET(&diff_opts, FIND_COPIES_HARDER); + 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]); + } +} |