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-rw-r--r--diff-cache.c267
1 files changed, 267 insertions, 0 deletions
diff --git a/diff-cache.c b/diff-cache.c
new file mode 100644
index 0000000..fcbc490
--- /dev/null
+++ b/diff-cache.c
@@ -0,0 +1,267 @@
+#include "cache.h"
+
+static int cached_only = 0;
+static int recursive = 0;
+static int line_termination = '\n';
+
+static int diff_cache(void *tree, unsigned long size, struct cache_entry **ac, int entries, const char *base);
+
+static void update_tree_entry(void **bufp, unsigned long *sizep)
+{
+ void *buf = *bufp;
+ unsigned long size = *sizep;
+ int len = strlen(buf) + 1 + 20;
+
+ if (size < len)
+ die("corrupt tree file 1 (%s)", size);
+ *bufp = buf + len;
+ *sizep = size - len;
+}
+
+static const unsigned char *extract(void *tree, unsigned long size, const char **pathp, unsigned int *modep)
+{
+ int len = strlen(tree)+1;
+ const unsigned char *sha1 = tree + len;
+ const char *path = strchr(tree, ' ');
+
+ if (!path || size < len + 20 || sscanf(tree, "%o", modep) != 1)
+ die("corrupt tree file 2 (%d)", size);
+ *pathp = path+1;
+ return sha1;
+}
+
+static char *malloc_base(const char *base, const char *path, int pathlen)
+{
+ int baselen = strlen(base);
+ char *newbase = malloc(baselen + pathlen + 2);
+ memcpy(newbase, base, baselen);
+ memcpy(newbase + baselen, path, pathlen);
+ memcpy(newbase + baselen + pathlen, "/", 2);
+ return newbase;
+}
+
+static void show_file(const char *prefix, const char *path, unsigned int mode, const unsigned char *sha1, const char *base);
+
+/* A whole sub-tree went away or appeared */
+static void show_tree(const char *prefix, void *tree, unsigned long size, const char *base)
+{
+ while (size) {
+ const char *path;
+ unsigned int mode;
+ const unsigned char *sha1 = extract(tree, size, &path, &mode);
+
+ show_file(prefix, path, mode, sha1, base);
+ update_tree_entry(&tree, &size);
+ }
+}
+
+/* A file entry went away or appeared */
+static void show_file(const char *prefix, const char *path, unsigned int mode, const unsigned char *sha1, const char *base)
+{
+ if (recursive && S_ISDIR(mode)) {
+ char type[20];
+ unsigned long size;
+ char *newbase = malloc_base(base, path, strlen(path));
+ void *tree;
+
+ tree = read_sha1_file(sha1, type, &size);
+ if (!tree || strcmp(type, "tree"))
+ die("corrupt tree sha %s", sha1_to_hex(sha1));
+
+ show_tree(prefix, tree, size, newbase);
+
+ free(tree);
+ free(newbase);
+ return;
+ }
+
+ printf("%s%o\t%s\t%s\t%s%s%c", prefix, mode,
+ S_ISDIR(mode) ? "tree" : "blob",
+ sha1_to_hex(sha1), base, path,
+ line_termination);
+}
+
+static int compare_tree_entry(const char *path1, unsigned int mode1, const unsigned char *sha1,
+ struct cache_entry **ac, int *entries, const char *base)
+{
+ int baselen = strlen(base);
+ struct cache_entry *ce = *ac;
+ const char *path2 = ce->name + baselen;
+ unsigned int mode2 = ntohl(ce->ce_mode);
+ const unsigned char *sha2 = ce->sha1;
+ int cmp, pathlen1, pathlen2;
+ char old_sha1_hex[50];
+
+ pathlen1 = strlen(path1);
+ pathlen2 = strlen(path2);
+ cmp = cache_name_compare(path1, pathlen1, path2, pathlen2);
+ if (cmp < 0) {
+ if (S_ISDIR(mode1)) {
+ char type[20];
+ unsigned long size;
+ void *tree = read_sha1_file(sha1, type, &size);
+ char *newbase = malloc(baselen + 2 + pathlen1);
+
+ memcpy(newbase, base, baselen);
+ memcpy(newbase + baselen, path1, pathlen1);
+ memcpy(newbase + baselen + pathlen1, "/", 2);
+ if (!tree || strcmp(type, "tree"))
+ die("unable to read tree object %s", sha1_to_hex(sha1));
+ *entries = diff_cache(tree, size, ac, *entries, newbase);
+ free(newbase);
+ free(tree);
+ return -1;
+ }
+ show_file("-", path1, mode1, sha1, base);
+ return -1;
+ }
+
+ if (!cached_only) {
+ static unsigned char no_sha1[20];
+ int fd, changed;
+ struct stat st;
+ fd = open(ce->name, O_RDONLY);
+ if (fd < 0 || fstat(fd, &st) < 0) {
+ show_file("-", path1, mode1, sha1, base);
+ return -1;
+ }
+ changed = cache_match_stat(ce, &st);
+ close(fd);
+ if (changed) {
+ mode2 = st.st_mode;
+ sha2 = no_sha1;
+ }
+ }
+
+ if (cmp > 0) {
+ show_file("+", path2, mode2, sha2, base);
+ return 1;
+ }
+ if (!memcmp(sha1, sha2, 20) && 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_file("-", path1, mode1, sha1, base);
+ show_file("+", path2, mode2, sha2, base);
+ return 0;
+ }
+
+ strcpy(old_sha1_hex, sha1_to_hex(sha1));
+ printf("*%o->%o\t%s\t%s->%s\t%s%s%c", mode1, mode2,
+ S_ISDIR(mode1) ? "tree" : "blob",
+ old_sha1_hex, sha1_to_hex(sha2), base, path1,
+ line_termination);
+ return 0;
+}
+
+static int diff_cache(void *tree, unsigned long size, struct cache_entry **ac, int entries, const char *base)
+{
+ int baselen = strlen(base);
+
+ for (;;) {
+ struct cache_entry *ce;
+ unsigned int mode;
+ const char *path;
+ const unsigned char *sha1;
+ int left;
+
+ /*
+ * No entries in the cache (with this base)?
+ * Output the tree contents.
+ */
+ if (!entries || ce_namelen(ce = *ac) < baselen || memcmp(ce->name, base, baselen)) {
+ if (!size)
+ return entries;
+ sha1 = extract(tree, size, &path, &mode);
+ show_file("-", path, mode, sha1, base);
+ update_tree_entry(&tree, &size);
+ continue;
+ }
+
+ /*
+ * No entries in the tree? Output the cache contents
+ */
+ if (!size) {
+ show_file("+", ce->name, ntohl(ce->ce_mode), ce->sha1, "");
+ ac++;
+ entries--;
+ continue;
+ }
+
+ sha1 = extract(tree, size, &path, &mode);
+ left = entries;
+ switch (compare_tree_entry(path, mode, sha1, ac, &left, base)) {
+ case -1:
+ update_tree_entry(&tree, &size);
+ if (left < entries) {
+ ac += (entries - left);
+ entries = left;
+ }
+ continue;
+ case 0:
+ update_tree_entry(&tree, &size);
+ /* Fallthrough */
+ case 1:
+ ac++;
+ entries--;
+ continue;
+ }
+ die("diff-cache: internal error");
+ }
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ unsigned char tree_sha1[20];
+ void *tree;
+ unsigned long size;
+ char type[20];
+
+ read_cache();
+ while (argc > 2) {
+ char *arg = argv[1];
+ argv++;
+ argc--;
+ if (!strcmp(arg, "-r")) {
+ recursive = 1;
+ continue;
+ }
+ if (!strcmp(arg, "-z")) {
+ line_termination = '\0';
+ continue;
+ }
+ if (!strcmp(arg, "--cached")) {
+ cached_only = 1;
+ continue;
+ }
+ usage("diff-cache [-r] [-z] <tree sha1>");
+ }
+
+ if (argc != 2 || get_sha1_hex(argv[1], tree_sha1))
+ usage("diff-cache [-r] [-z] <tree sha1>");
+
+ tree = read_sha1_file(tree_sha1, type, &size);
+ if (!tree)
+ die("bad tree object %s", argv[1]);
+
+ /* We allow people to feed us a commit object, just because we're nice */
+ if (!strcmp(type, "commit")) {
+ /* tree sha1 is always at offset 5 ("tree ") */
+ if (get_sha1_hex(tree + 5, tree_sha1))
+ die("bad commit object %s", argv[1]);
+ free(tree);
+ tree = read_sha1_file(tree_sha1, type, &size);
+ if (!tree)
+ die("unable to read tree object %s", sha1_to_hex(tree_sha1));
+ }
+
+ if (strcmp(type, "tree"))
+ die("bad tree object %s (%s)", sha1_to_hex(tree_sha1), type);
+
+ return diff_cache(tree, size, active_cache, active_nr, "");
+}