diff options
| -rw-r--r-- | Makefile | 5 | ||||
| -rw-r--r-- | diff-tree.c | 109 |
2 files changed, 113 insertions, 1 deletions
@@ -2,7 +2,7 @@ CFLAGS=-g -O3 -Wall CC=gcc PROG= update-cache show-diff init-db write-tree read-tree commit-tree \ - cat-file fsck-cache checkout-cache + cat-file fsck-cache checkout-cache diff-tree all: $(PROG) @@ -37,6 +37,9 @@ fsck-cache: fsck-cache.o read-cache.o checkout-cache: checkout-cache.o read-cache.o $(CC) $(CFLAGS) -o checkout-cache checkout-cache.o read-cache.o $(LIBS) +diff-tree: diff-tree.o read-cache.o + $(CC) $(CFLAGS) -o diff-tree diff-tree.o read-cache.o $(LIBS) + read-cache.o: cache.h show-diff.o: cache.h diff --git a/diff-tree.c b/diff-tree.c new file mode 100644 index 0000000..2f04d1e --- /dev/null +++ b/diff-tree.c @@ -0,0 +1,109 @@ +#include "cache.h" + +struct tree_entry; + +static struct tree_entry *update_tree_entry(void **bufp, unsigned long *sizep) +{ + void *buf = *bufp; + unsigned long size = *sizep; + int len = strlen(buf) + 1 + 20; + + if (size < len) + usage("corrupt tree file"); + *bufp = buf + len; + *sizep = size - len; + return buf; +} + +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) + usage("corrupt tree file"); + *pathp = path+1; + return sha1; +} + +static void show_file(const char *prefix, void *tree, unsigned long size) +{ + unsigned mode; + const char *path; + const unsigned char *sha1 = extract(tree, size, &path, &mode); + printf("%s%o %s %s%c", prefix, mode, sha1_to_hex(sha1), path, 0); +} + +static int compare_tree_entry(void *tree1, unsigned long size1, void *tree2, unsigned long size2) +{ + unsigned mode1, mode2; + const char *path1, *path2; + const unsigned char *sha1, *sha2; + int cmp; + + sha1 = extract(tree1, size1, &path1, &mode1); + sha2 = extract(tree2, size2, &path2, &mode2); + + cmp = cache_name_compare(path1, strlen(path1), path2, strlen(path2)); + if (cmp < 0) { + show_file("-", tree1, size1); + return -1; + } + if (cmp > 0) { + show_file("+", tree2, size2); + return 1; + } + if (!memcmp(sha1, sha2, 20) && mode1 == mode2) + return 0; + show_file("<", tree1, size1); + show_file(">", tree2, size2); + return 0; +} + +static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned long size2) +{ + while (size1 | size2) { + if (!size1) { + show_file("+", tree2, size2); + update_tree_entry(&tree2, &size2); + continue; + } + if (!size2) { + show_file("-", tree1, size1); + update_tree_entry(&tree1, &size1); + continue; + } + switch (compare_tree_entry(tree1, size1, tree2, size2)) { + case -1: + update_tree_entry(&tree1, &size1); + continue; + case 0: + update_tree_entry(&tree1, &size1); + /* Fallthrough */ + case 1: + update_tree_entry(&tree2, &size2); + continue; + } + usage("diff-tree: internal error"); + } + return 0; +} + +int main(int argc, char **argv) +{ + unsigned char old[20], new[20]; + void *tree1, *tree2; + unsigned long size1, size2; + char type[20]; + + if (argc != 3 || get_sha1_hex(argv[1], old) || get_sha1_hex(argv[2], new)) + usage("diff-tree <tree sha1> <tree sha1>"); + tree1 = read_sha1_file(old, type, &size1); + if (!tree1 || strcmp(type, "tree")) + usage("unable to read source tree"); + tree2 = read_sha1_file(new, type, &size2); + if (!tree2 || strcmp(type, "tree")) + usage("unable to read destination tree"); + return diff_tree(tree1, size1, tree2, size2); +} |