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![Linus Torvalds](/assets/img/avatar_default.png)
This makes the tree diff functionality independent of the "git-diff-tree" program, by splitting the core functionality up into a library file. This will be needed for when we teach git-rev-list to only follow a specified set of pathnames, rather than the global revision history. Most of it is a fairly straightforward code move, but it also involves some calling convention cleanup, and moving some of the static variables from diff-tree.c into the options structure. The actual tree change callback routines also become paramterized by the diff_options structure, allowing the library functionality to do something else than just show the diff on stdout. Right now the only user of this functionality remains git-diff-tree itself. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
271 lines
6.1 KiB
C
271 lines
6.1 KiB
C
/*
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* Helper functions for tree diff generation
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*/
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#include "cache.h"
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#include "diff.h"
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// What paths are we interested in?
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static int nr_paths = 0;
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static const char **paths = NULL;
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static int *pathlens = NULL;
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static void update_tree_entry(struct tree_desc *desc)
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{
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void *buf = desc->buf;
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unsigned long size = desc->size;
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int len = strlen(buf) + 1 + 20;
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if (size < len)
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die("corrupt tree file");
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desc->buf = buf + len;
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desc->size = size - len;
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}
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static const unsigned char *extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)
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{
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void *tree = desc->buf;
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unsigned long size = desc->size;
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int len = strlen(tree)+1;
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const unsigned char *sha1 = tree + len;
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const char *path = strchr(tree, ' ');
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unsigned int mode;
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if (!path || size < len + 20 || sscanf(tree, "%o", &mode) != 1)
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die("corrupt tree file");
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*pathp = path+1;
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*modep = DIFF_FILE_CANON_MODE(mode);
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return sha1;
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}
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static char *malloc_base(const char *base, const char *path, int pathlen)
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{
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int baselen = strlen(base);
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char *newbase = xmalloc(baselen + pathlen + 2);
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memcpy(newbase, base, baselen);
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memcpy(newbase + baselen, path, pathlen);
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memcpy(newbase + baselen + pathlen, "/", 2);
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return newbase;
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}
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static int show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base);
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static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
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{
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unsigned mode1, mode2;
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const char *path1, *path2;
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const unsigned char *sha1, *sha2;
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int cmp, pathlen1, pathlen2;
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sha1 = extract(t1, &path1, &mode1);
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sha2 = extract(t2, &path2, &mode2);
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pathlen1 = strlen(path1);
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pathlen2 = strlen(path2);
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cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
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if (cmp < 0) {
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show_entry(opt, "-", t1, base);
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return -1;
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}
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if (cmp > 0) {
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show_entry(opt, "+", t2, base);
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return 1;
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}
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if (!opt->find_copies_harder &&
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!memcmp(sha1, sha2, 20) && mode1 == mode2)
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return 0;
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/*
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* If the filemode has changed to/from a directory from/to a regular
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* file, we need to consider it a remove and an add.
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*/
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if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
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show_entry(opt, "-", t1, base);
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show_entry(opt, "+", t2, base);
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return 0;
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}
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if (opt->recursive && S_ISDIR(mode1)) {
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int retval;
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char *newbase = malloc_base(base, path1, pathlen1);
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if (opt->tree_in_recursive)
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opt->change(opt, mode1, mode2,
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sha1, sha2, base, path1);
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retval = diff_tree_sha1(sha1, sha2, newbase, opt);
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free(newbase);
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return retval;
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}
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opt->change(opt, mode1, mode2, sha1, sha2, base, path1);
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return 0;
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}
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static int interesting(struct tree_desc *desc, const char *base)
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{
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const char *path;
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unsigned mode;
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int i;
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int baselen, pathlen;
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if (!nr_paths)
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return 1;
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(void)extract(desc, &path, &mode);
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pathlen = strlen(path);
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baselen = strlen(base);
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for (i=0; i < nr_paths; i++) {
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const char *match = paths[i];
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int matchlen = pathlens[i];
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if (baselen >= matchlen) {
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/* If it doesn't match, move along... */
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if (strncmp(base, match, matchlen))
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continue;
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/* The base is a subdirectory of a path which was specified. */
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return 1;
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}
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/* Does the base match? */
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if (strncmp(base, match, baselen))
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continue;
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match += baselen;
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matchlen -= baselen;
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if (pathlen > matchlen)
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continue;
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if (matchlen > pathlen) {
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if (match[pathlen] != '/')
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continue;
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if (!S_ISDIR(mode))
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continue;
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}
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if (strncmp(path, match, pathlen))
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continue;
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return 1;
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}
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return 0; /* No matches */
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}
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/* A whole sub-tree went away or appeared */
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static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)
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{
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while (desc->size) {
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if (interesting(desc, base))
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show_entry(opt, prefix, desc, base);
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update_tree_entry(desc);
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}
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}
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/* A file entry went away or appeared */
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static int show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)
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{
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unsigned mode;
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const char *path;
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const unsigned char *sha1 = extract(desc, &path, &mode);
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if (opt->recursive && S_ISDIR(mode)) {
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char type[20];
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char *newbase = malloc_base(base, path, strlen(path));
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struct tree_desc inner;
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void *tree;
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tree = read_sha1_file(sha1, type, &inner.size);
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if (!tree || strcmp(type, "tree"))
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die("corrupt tree sha %s", sha1_to_hex(sha1));
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inner.buf = tree;
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show_tree(opt, prefix, &inner, newbase);
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free(tree);
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free(newbase);
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return 0;
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}
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opt->add_remove(opt, prefix[0], mode, sha1, base, path);
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return 0;
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}
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int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
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{
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while (t1->size | t2->size) {
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if (nr_paths && t1->size && !interesting(t1, base)) {
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update_tree_entry(t1);
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continue;
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}
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if (nr_paths && t2->size && !interesting(t2, base)) {
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update_tree_entry(t2);
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continue;
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}
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if (!t1->size) {
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show_entry(opt, "+", t2, base);
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update_tree_entry(t2);
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continue;
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}
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if (!t2->size) {
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show_entry(opt, "-", t1, base);
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update_tree_entry(t1);
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continue;
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}
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switch (compare_tree_entry(t1, t2, base, opt)) {
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case -1:
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update_tree_entry(t1);
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continue;
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case 0:
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update_tree_entry(t1);
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/* Fallthrough */
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case 1:
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update_tree_entry(t2);
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continue;
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}
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die("git-diff-tree: internal error");
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}
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return 0;
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}
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int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
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{
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void *tree1, *tree2;
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struct tree_desc t1, t2;
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int retval;
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tree1 = read_object_with_reference(old, "tree", &t1.size, NULL);
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if (!tree1)
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die("unable to read source tree (%s)", sha1_to_hex(old));
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tree2 = read_object_with_reference(new, "tree", &t2.size, NULL);
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if (!tree2)
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die("unable to read destination tree (%s)", sha1_to_hex(new));
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t1.buf = tree1;
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t2.buf = tree2;
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retval = diff_tree(&t1, &t2, base, opt);
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free(tree1);
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free(tree2);
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return retval;
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}
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static int count_paths(const char **paths)
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{
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int i = 0;
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while (*paths++)
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i++;
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return i;
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}
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void diff_tree_setup_paths(const char **p)
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{
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if (p) {
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int i;
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paths = p;
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nr_paths = count_paths(paths);
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pathlens = xmalloc(nr_paths * sizeof(int));
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for (i=0; i<nr_paths; i++)
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pathlens[i] = strlen(paths[i]);
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}
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}
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