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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-09 20:00:54 (GMT)
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-09 20:00:54 (GMT)
commit9174026cfe69d73ef80b27890615f8b2ef5c265a (patch)
treed4a96ba891017d0d26c15e509b4e6515e40d75ee /diff-tree.c
parent79517a067a293ddf19867e363f0d9237c7ef8e22 (diff)
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Add "diff-tree" program to show which files have changed between two trees.
Very useful for creating diffs efficiently, and in general to see what has changed in the namespace.
Diffstat (limited to 'diff-tree.c')
-rw-r--r--diff-tree.c109
1 files changed, 109 insertions, 0 deletions
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);
+}