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New "diff-cache" implementation.
This one is about a million times simpler, and much more likely to be correct too. Instead of trying to match up a tree object against the index, we just read in the tree object side-by-side into the index, and just walk the resulting index file. This was what all the read-tree cleanups were all getting to.
This commit is contained in:
Linus Torvalds
parent
94537c78a8
commit
b5af910727
2
cache.h
2
cache.h
@ -99,7 +99,9 @@ extern int read_cache(void);
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extern int write_cache(int newfd, struct cache_entry **cache, int entries);
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extern int cache_name_pos(const char *name, int namelen);
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extern int add_cache_entry(struct cache_entry *ce, int ok_to_add);
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extern int remove_entry_at(int pos);
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extern int remove_file_from_cache(char *path);
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extern int same_name(struct cache_entry *a, struct cache_entry *b);
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extern int cache_match_stat(struct cache_entry *ce, struct stat *st);
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#define MTIME_CHANGED 0x0001
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234
diff-cache.c
234
diff-cache.c
@ -1,220 +1,90 @@
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#include "cache.h"
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static int cached_only = 0;
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static int recursive = 0;
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static int line_termination = '\n';
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static int diff_cache(void *tree, unsigned long size, struct cache_entry **ac, int entries, 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 1 (%s)", size);
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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 2 (%d)", size);
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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 = malloc(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, const char *path, unsigned int mode, const unsigned char *sha1, 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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const char *path;
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unsigned int mode;
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const unsigned char *sha1 = extract(tree, size, &path, &mode);
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show_file(prefix, path, mode, sha1, 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, const char *path, unsigned int mode, const unsigned char *sha1, const char *base)
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static void show_file(const char *prefix, struct cache_entry *ce)
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{
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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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printf("%s%o\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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printf("%s%o\t%s\t%s\t%s%c", prefix, ntohl(ce->ce_mode), "blob",
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sha1_to_hex(ce->sha1), ce->name, line_termination);
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}
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static int compare_tree_entry(const char *path1, unsigned int mode1, const unsigned char *sha1,
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struct cache_entry **ac, int *entries, const char *base)
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static int show_modified(struct cache_entry *old, struct cache_entry *new)
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{
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int baselen = strlen(base);
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struct cache_entry *ce = *ac;
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const char *path2 = ce->name + baselen;
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unsigned int mode2 = ntohl(ce->ce_mode);
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const unsigned char *sha2 = ce->sha1;
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int cmp, pathlen1, pathlen2;
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char old_sha1_hex[50];
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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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if (S_ISDIR(mode1)) {
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char type[20];
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unsigned long size;
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void *tree = read_sha1_file(sha1, type, &size);
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char *newbase = malloc(baselen + 2 + pathlen1);
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memcpy(newbase, base, baselen);
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memcpy(newbase + baselen, path1, pathlen1);
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memcpy(newbase + baselen + pathlen1, "/", 2);
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if (!tree || strcmp(type, "tree"))
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die("unable to read tree object %s", sha1_to_hex(sha1));
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*entries = diff_cache(tree, size, ac, *entries, newbase);
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free(newbase);
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free(tree);
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return -1;
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}
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show_file("-", path1, mode1, sha1, base);
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return -1;
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}
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unsigned int mode = ntohl(new->ce_mode), oldmode;
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unsigned char *sha1 = new->sha1;
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unsigned char old_sha1_hex[60];
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if (!cached_only) {
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static unsigned char no_sha1[20];
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int fd, changed;
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int changed;
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struct stat st;
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fd = open(ce->name, O_RDONLY);
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if (fd < 0 || fstat(fd, &st) < 0) {
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show_file("-", path1, mode1, sha1, base);
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if (stat(new->name, &st) < 0) {
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show_file("-", old);
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return -1;
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}
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changed = cache_match_stat(ce, &st);
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close(fd);
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changed = cache_match_stat(new, &st);
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if (changed) {
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mode2 = st.st_mode;
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sha2 = no_sha1;
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mode = st.st_mode;
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sha1 = no_sha1;
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}
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}
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if (cmp > 0) {
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show_file("+", path2, mode2, sha2, 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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oldmode = ntohl(old->ce_mode);
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if (mode == oldmode && !memcmp(sha1, old->sha1, 20))
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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("-", path1, mode1, sha1, base);
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show_file("+", path2, mode2, sha2, base);
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return 0;
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}
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strcpy(old_sha1_hex, sha1_to_hex(sha1));
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printf("*%o->%o\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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strcpy(old_sha1_hex, sha1_to_hex(old->sha1));
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printf("*%o->%o\t%s\t%s->%s\t%s%c", oldmode, mode,
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"blob",
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old_sha1_hex, sha1_to_hex(sha1),
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old->name, line_termination);
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return 0;
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}
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static int diff_cache(void *tree, unsigned long size, struct cache_entry **ac, int entries, const char *base)
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static int diff_cache(struct cache_entry **ac, int entries)
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{
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int baselen = strlen(base);
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while (entries) {
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struct cache_entry *ce = *ac;
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for (;;) {
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struct cache_entry *ce;
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unsigned int mode;
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const char *path;
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const unsigned char *sha1;
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int left;
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/*
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* No entries in the cache (with this base)?
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* Output the tree contents.
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*/
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if (!entries || ce_namelen(ce = *ac) < baselen || memcmp(ce->name, base, baselen)) {
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if (!size)
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return entries;
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sha1 = extract(tree, size, &path, &mode);
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show_file("-", path, mode, sha1, base);
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update_tree_entry(&tree, &size);
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continue;
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}
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/*
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* No entries in the tree? Output the cache contents
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*/
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if (!size) {
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show_file("+", ce->name, ntohl(ce->ce_mode), ce->sha1, "");
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/* No matching 0-stage (current) entry? Show it as deleted */
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if (ce_stage(ce)) {
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show_file("-", ce);
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ac++;
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entries--;
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continue;
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}
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sha1 = extract(tree, size, &path, &mode);
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left = entries;
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switch (compare_tree_entry(path, mode, sha1, ac, &left, base)) {
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case -1:
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update_tree_entry(&tree, &size);
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if (left < entries) {
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ac += (entries - left);
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entries = left;
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}
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continue;
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case 0:
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update_tree_entry(&tree, &size);
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/* Fallthrough */
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case 1:
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/* No matching 1-stage (tree) entry? Show the current one as added */
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if (entries == 1 || !same_name(ce, ac[1])) {
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show_file("-", ce);
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ac++;
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entries--;
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continue;
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}
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die("diff-cache: internal error");
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show_modified(ac[1], ce);
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ac += 2;
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entries -= 2;
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continue;
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}
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return 0;
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}
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static void remove_merge_entries(void)
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{
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int i;
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for (i = 0; i < active_nr; i++) {
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struct cache_entry *ce = active_cache[i];
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if (!ce_stage(ce))
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break;
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printf("%s: unmerged\n", ce->name);
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while (remove_entry_at(i)) {
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if (!ce_stage(active_cache[i]))
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break;
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}
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}
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}
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static char *diff_cache_usage = "diff-cache [-r] [-z] [--cached] <tree sha1>";
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int main(int argc, char **argv)
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@ -229,7 +99,7 @@ int main(int argc, char **argv)
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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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/* We accept the -r flag just to look like diff-tree */
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continue;
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}
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if (!strcmp(arg, "-z")) {
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@ -246,9 +116,13 @@ int main(int argc, char **argv)
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if (argc != 2 || get_sha1_hex(argv[1], tree_sha1))
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usage(diff_cache_usage);
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remove_merge_entries();
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tree = read_tree_with_tree_or_commit_sha1(tree_sha1, &size, 0);
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if (!tree)
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die("bad tree object %s", argv[1]);
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if (read_tree(tree, size, 1))
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die("unable to read tree object %s", argv[1]);
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return diff_cache(tree, size, active_cache, active_nr, "");
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return diff_cache(active_cache, active_nr);
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}
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@ -87,7 +87,7 @@ int cache_name_pos(const char *name, int namelen)
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}
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/* Remove entry, return true if there are more entries to go.. */
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static int remove_entry_at(int pos)
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int remove_entry_at(int pos)
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{
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active_nr--;
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if (pos >= active_nr)
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@ -106,7 +106,7 @@ int remove_file_from_cache(char *path)
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return 0;
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}
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static int same_name(struct cache_entry *a, struct cache_entry *b)
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int same_name(struct cache_entry *a, struct cache_entry *b)
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{
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int len = ce_namelen(a);
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return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
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