Add "-R" flag to "diff-tree", so that it will recursively traverse a tree of trees

as it diffs them.

This makes diff-tree usable again in the new world order.

cache.h

@@ -87,15 +87,15 @@ extern int cache_match_stat(struct cache_entry *ce, struct stat *st);
 #define DATA_CHANGED    0x0020
 
 /* Return a statically allocated filename matching the sha1 signature */
-extern char *sha1_file_name(unsigned char *sha1);
+extern char *sha1_file_name(const unsigned char *sha1);
 
 /* Write a memory buffer out to the sha file */
-extern int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size);
+extern int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size);
 
 /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
-extern void * map_sha1_file(unsigned char *sha1, unsigned long *size);
+extern void * map_sha1_file(const unsigned char *sha1, unsigned long *size);
 extern void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size);
-extern void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size);
+extern void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size);
 extern int write_sha1_file(char *buf, unsigned len, unsigned char *return_sha1);
 extern int check_sha1_signature(unsigned char *sha1, void *buf, unsigned long size);
 

diff-tree.c

 #include "cache.h"
 
-struct tree_entry;
+static int recursive = 0;
 
-static struct tree_entry *update_tree_entry(void **bufp, unsigned long *sizep)
+static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *src, const char *dst);
+
+static void update_tree_entry(void **bufp, unsigned long *sizep)
 {
 	void *buf = *bufp;
 	unsigned long size = *sizep;
@@ -12,7 +14,6 @@ static struct tree_entry *update_tree_entry(void **bufp, unsigned long *sizep)
 		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)
@@ -27,54 +28,70 @@ static const unsigned char *extract(void *tree, unsigned long size, const char *
 	return sha1;
 }
 
-static void show_file(const char *prefix, void *tree, unsigned long size)
+static void show_file(const char *prefix, void *tree, unsigned long size, const char *base)
 {
 	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);
+	printf("%s%o %s %s%s%c", prefix, mode, sha1_to_hex(sha1), base, path, 0);
 }
 
-static int compare_tree_entry(void *tree1, unsigned long size1, void *tree2, unsigned long size2)
+static int compare_tree_entry(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *src, const char *dst)
 {
 	unsigned mode1, mode2;
 	const char *path1, *path2;
 	const unsigned char *sha1, *sha2;
-	int cmp;
+	int cmp, pathlen1, pathlen2;
 
 	sha1 = extract(tree1, size1, &path1, &mode1);
 	sha2 = extract(tree2, size2, &path2, &mode2);
 
-	cmp = cache_name_compare(path1, strlen(path1), path2, strlen(path2));
+	pathlen1 = strlen(path1);
+	pathlen2 = strlen(path2);
+	cmp = cache_name_compare(path1, pathlen1, path2, pathlen2);
 	if (cmp < 0) {
-		show_file("-", tree1, size1);
+		show_file("-", tree1, size1, src);
 		return -1;
 	}
 	if (cmp > 0) {
-		show_file("+", tree2, size2);
+		show_file("+", tree2, size2, dst);
 		return 1;
 	}
 	if (!memcmp(sha1, sha2, 20) && mode1 == mode2)
 		return 0;
-	show_file("<", tree1, size1);
-	show_file(">", tree2, size2);
+	if (recursive && S_ISDIR(mode1) && S_ISDIR(mode2)) {
+		int srclen = strlen(src);
+		int dstlen = strlen(dst);
+		char *srcbase = malloc(srclen + pathlen1 + 2);
+		char *dstbase = malloc(srclen + pathlen1 + 2);
+		memcpy(srcbase, src, srclen);
+		memcpy(srcbase + srclen, path1, pathlen1);
+		memcpy(srcbase + srclen + pathlen1, "/", 2);
+		memcpy(dstbase, dst, dstlen);
+		memcpy(dstbase + dstlen, path2, pathlen2);
+		memcpy(dstbase + dstlen + pathlen2, "/", 2);
+		return diff_tree_sha1(sha1, sha2, srcbase, dstbase);
+	}
+
+	show_file("<", tree1, size1, src);
+	show_file(">", tree2, size2, dst);
 	return 0;
 }
 
-static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned long size2)
+static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *src, const char *dst)
 {
 	while (size1 | size2) {
 		if (!size1) {
-			show_file("+", tree2, size2);
+			show_file("+", tree2, size2, dst);
 			update_tree_entry(&tree2, &size2);
 			continue;
 		}
 		if (!size2) {
-			show_file("-", tree1, size1);
+			show_file("-", tree1, size1, src);
 			update_tree_entry(&tree1, &size1);
 			continue;
 		}
-		switch (compare_tree_entry(tree1, size1, tree2, size2)) {
+		switch (compare_tree_entry(tree1, size1, tree2, size2, src, dst)) {
 		case -1:
 			update_tree_entry(&tree1, &size1);
 			continue;
@@ -90,20 +107,41 @@ static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned lon
 	return 0;
 }
 
-int main(int argc, char **argv)
+static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *src, const char *dst)
 {
-	unsigned char old[20], new[20];
 	void *tree1, *tree2;
 	unsigned long size1, size2;
 	char type[20];
+	int retval;
 
-	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);
+	retval = diff_tree(tree1, size1, tree2, size2, src, dst);
+	free(tree1);
+	free(tree2);
+	return retval;
+}
+
+int main(int argc, char **argv)
+{
+	unsigned char old[20], new[20];
+
+	while (argc > 3) {
+		char *arg = argv[1];
+		argv++;
+		argc--;
+		if (!strcmp(arg, "-R")) {
+			recursive = 1;
+			continue;
+		}
+		usage("diff-tree [-R] <tree sha1> <tree sha1>");
+	}
+
+	if (argc != 3 || get_sha1_hex(argv[1], old) || get_sha1_hex(argv[2], new))
+		usage("diff-tree <tree sha1> <tree sha1>");
+	return diff_tree_sha1(old, new, "", "");
 }

read-cache.c

@@ -63,7 +63,7 @@ char * sha1_to_hex(const unsigned char *sha1)
  * careful about using it. Do a "strdup()" if you need to save the
  * filename.
  */
-char *sha1_file_name(unsigned char *sha1)
+char *sha1_file_name(const unsigned char *sha1)
 {
 	int i;
 	static char *name, *base;
@@ -99,7 +99,7 @@ int check_sha1_signature(unsigned char *sha1, void *map, unsigned long size)
 	return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 }
 
-void *map_sha1_file(unsigned char *sha1, unsigned long *size)
+void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 {
 	char *filename = sha1_file_name(sha1);
 	int fd = open(filename, O_RDONLY);
@@ -158,7 +158,7 @@ void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned l
 	return buf;
 }
 
-void * read_sha1_file(unsigned char *sha1, char *type, unsigned long *size)
+void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
 {
 	unsigned long mapsize;
 	void *map, *buf;
@@ -208,7 +208,7 @@ int write_sha1_file(char *buf, unsigned len, unsigned char *returnsha1)
 	return 0;
 }
 
-int write_sha1_buffer(unsigned char *sha1, void *buf, unsigned int size)
+int write_sha1_buffer(const unsigned char *sha1, void *buf, unsigned int size)
 {
 	char *filename = sha1_file_name(sha1);
 	int fd;