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![Linus Torvalds](/assets/img/avatar_default.png)
This allows the programs to use various simplified versions of the SHA1 names, eg just say "HEAD" for the SHA1 pointed to by the .git/HEAD file etc. For example, this commit has been done with git-commit-tree $(git-write-tree) -p HEAD instead of the traditional "$(cat .git/HEAD)" syntax.
297 lines
6.8 KiB
C
297 lines
6.8 KiB
C
#include "cache.h"
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#include "diff.h"
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static int recursive = 0;
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static int line_termination = '\n';
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static int generate_patch = 0;
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// What paths are we interested in?
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static int nr_paths = 0;
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static char **paths = NULL;
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static int *pathlens = NULL;
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static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base);
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static void update_tree_entry(void **bufp, unsigned long *sizep)
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{
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void *buf = *bufp;
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unsigned long size = *sizep;
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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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*bufp = buf + len;
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*sizep = size - len;
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}
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static const unsigned char *extract(void *tree, unsigned long size, const char **pathp, unsigned int *modep)
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{
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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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if (!path || size < len + 20 || sscanf(tree, "%o", modep) != 1)
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die("corrupt tree file");
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*pathp = path+1;
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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 void show_file(const char *prefix, void *tree, unsigned long size, const char *base);
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/* A whole sub-tree went away or appeared */
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static void show_tree(const char *prefix, void *tree, unsigned long size, const char *base)
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{
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while (size) {
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show_file(prefix, tree, size, base);
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update_tree_entry(&tree, &size);
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}
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}
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/* A file entry went away or appeared */
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static void show_file(const char *prefix, void *tree, unsigned long size, 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(tree, size, &path, &mode);
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if (recursive && S_ISDIR(mode)) {
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char type[20];
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unsigned long size;
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char *newbase = malloc_base(base, path, strlen(path));
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void *tree;
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tree = read_sha1_file(sha1, type, &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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show_tree(prefix, tree, size, newbase);
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free(tree);
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free(newbase);
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return;
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}
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if (generate_patch) {
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if (!S_ISDIR(mode))
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diff_addremove(prefix[0], mode, sha1, base, path);
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}
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else
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printf("%s%06o\t%s\t%s\t%s%s%c", prefix, mode,
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S_ISDIR(mode) ? "tree" : "blob",
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sha1_to_hex(sha1), base, path,
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line_termination);
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}
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static int compare_tree_entry(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
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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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char old_sha1_hex[50];
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sha1 = extract(tree1, size1, &path1, &mode1);
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sha2 = extract(tree2, size2, &path2, &mode2);
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pathlen1 = strlen(path1);
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pathlen2 = strlen(path2);
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cmp = cache_name_compare(path1, pathlen1, path2, pathlen2);
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if (cmp < 0) {
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show_file("-", tree1, size1, base);
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return -1;
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}
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if (cmp > 0) {
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show_file("+", tree2, size2, base);
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return 1;
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}
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if (!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_file("-", tree1, size1, base);
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show_file("+", tree2, size2, base);
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return 0;
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}
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if (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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retval = diff_tree_sha1(sha1, sha2, newbase);
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free(newbase);
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return retval;
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}
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if (generate_patch) {
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if (!S_ISDIR(mode1))
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diff_change(mode1, mode2, sha1, sha2, base, path1);
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}
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else {
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strcpy(old_sha1_hex, sha1_to_hex(sha1));
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printf("*%06o->%06o\t%s\t%s->%s\t%s%s%c", mode1, mode2,
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S_ISDIR(mode1) ? "tree" : "blob",
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old_sha1_hex, sha1_to_hex(sha2), base, path1,
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line_termination);
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}
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return 0;
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}
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static int interesting(void *tree, unsigned long size, 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(tree, size, &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 (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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static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
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{
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while (size1 | size2) {
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if (nr_paths && size1 && !interesting(tree1, size1, base)) {
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update_tree_entry(&tree1, &size1);
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continue;
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}
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if (nr_paths && size2 && !interesting(tree2, size2, base)) {
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update_tree_entry(&tree2, &size2);
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continue;
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}
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if (!size1) {
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show_file("+", tree2, size2, base);
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update_tree_entry(&tree2, &size2);
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continue;
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}
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if (!size2) {
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show_file("-", tree1, size1, base);
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update_tree_entry(&tree1, &size1);
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continue;
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}
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switch (compare_tree_entry(tree1, size1, tree2, size2, base)) {
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case -1:
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update_tree_entry(&tree1, &size1);
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continue;
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case 0:
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update_tree_entry(&tree1, &size1);
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/* Fallthrough */
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case 1:
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update_tree_entry(&tree2, &size2);
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continue;
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}
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die("diff-tree: internal error");
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}
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return 0;
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}
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static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base)
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{
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void *tree1, *tree2;
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unsigned long size1, size2;
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int retval;
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tree1 = read_object_with_reference(old, "tree", &size1, 0);
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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", &size2, 0);
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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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retval = diff_tree(tree1, size1, tree2, size2, base);
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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 char *diff_tree_usage = "diff-tree [-r] [-z] <tree sha1> <tree sha1>";
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int main(int argc, char **argv)
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{
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unsigned char old[20], new[20];
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for (;;) {
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char *arg = argv[1];
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if (!arg || *arg != '-')
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break;
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argv++;
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argc--;
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if (!strcmp(arg, "-r")) {
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recursive = 1;
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continue;
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}
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if (!strcmp(arg, "-p")) {
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recursive = generate_patch = 1;
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continue;
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}
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if (!strcmp(arg, "-z")) {
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line_termination = '\0';
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continue;
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}
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usage(diff_tree_usage);
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}
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if (argc < 3 || get_sha1(argv[1], old) || get_sha1(argv[2], new))
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usage(diff_tree_usage);
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if (argc > 3) {
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int i;
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paths = &argv[3];
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nr_paths = argc - 3;
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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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return diff_tree_sha1(old, new, "");
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}
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