summaryrefslogtreecommitdiff
path: root/tree-diff.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@osdl.org>2005-10-21 04:05:05 (GMT)
committerJunio C Hamano <junkio@cox.net>2005-10-23 05:49:51 (GMT)
commitac1b3d1248f36b26c2eab55022b9a54bde36b1ee (patch)
treec7b164aa108d7ea6722dc6dc0c305eae3fe5b08c /tree-diff.c
parent4f692b19788364ed0bd65983579edcd6e5444f2b (diff)
downloadgit-ac1b3d1248f36b26c2eab55022b9a54bde36b1ee.zip
git-ac1b3d1248f36b26c2eab55022b9a54bde36b1ee.tar.gz
git-ac1b3d1248f36b26c2eab55022b9a54bde36b1ee.tar.bz2
Split up tree diff functions into tree-diff.c library
This makes the tree diff functionality independent of the "git-diff-tree" program, by splitting the core functionality up into a library file. This will be needed for when we teach git-rev-list to only follow a specified set of pathnames, rather than the global revision history. Most of it is a fairly straightforward code move, but it also involves some calling convention cleanup, and moving some of the static variables from diff-tree.c into the options structure. The actual tree change callback routines also become paramterized by the diff_options structure, allowing the library functionality to do something else than just show the diff on stdout. Right now the only user of this functionality remains git-diff-tree itself. Signed-off-by: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Junio C Hamano <junkio@cox.net>
Diffstat (limited to 'tree-diff.c')
-rw-r--r--tree-diff.c270
1 files changed, 270 insertions, 0 deletions
diff --git a/tree-diff.c b/tree-diff.c
new file mode 100644
index 0000000..0ef06a9
--- /dev/null
+++ b/tree-diff.c
@@ -0,0 +1,270 @@
+/*
+ * Helper functions for tree diff generation
+ */
+#include "cache.h"
+#include "diff.h"
+
+// What paths are we interested in?
+static int nr_paths = 0;
+static const char **paths = NULL;
+static int *pathlens = NULL;
+
+static void update_tree_entry(struct tree_desc *desc)
+{
+ void *buf = desc->buf;
+ unsigned long size = desc->size;
+ int len = strlen(buf) + 1 + 20;
+
+ if (size < len)
+ die("corrupt tree file");
+ desc->buf = buf + len;
+ desc->size = size - len;
+}
+
+static const unsigned char *extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)
+{
+ void *tree = desc->buf;
+ unsigned long size = desc->size;
+ int len = strlen(tree)+1;
+ const unsigned char *sha1 = tree + len;
+ const char *path = strchr(tree, ' ');
+ unsigned int mode;
+
+ if (!path || size < len + 20 || sscanf(tree, "%o", &mode) != 1)
+ die("corrupt tree file");
+ *pathp = path+1;
+ *modep = DIFF_FILE_CANON_MODE(mode);
+ return sha1;
+}
+
+static char *malloc_base(const char *base, const char *path, int pathlen)
+{
+ int baselen = strlen(base);
+ char *newbase = xmalloc(baselen + pathlen + 2);
+ memcpy(newbase, base, baselen);
+ memcpy(newbase + baselen, path, pathlen);
+ memcpy(newbase + baselen + pathlen, "/", 2);
+ return newbase;
+}
+
+static int show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base);
+
+static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
+{
+ unsigned mode1, mode2;
+ const char *path1, *path2;
+ const unsigned char *sha1, *sha2;
+ int cmp, pathlen1, pathlen2;
+
+ sha1 = extract(t1, &path1, &mode1);
+ sha2 = extract(t2, &path2, &mode2);
+
+ pathlen1 = strlen(path1);
+ pathlen2 = strlen(path2);
+ cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
+ if (cmp < 0) {
+ show_entry(opt, "-", t1, base);
+ return -1;
+ }
+ if (cmp > 0) {
+ show_entry(opt, "+", t2, base);
+ return 1;
+ }
+ if (!opt->find_copies_harder &&
+ !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_entry(opt, "-", t1, base);
+ show_entry(opt, "+", t2, base);
+ return 0;
+ }
+
+ if (opt->recursive && S_ISDIR(mode1)) {
+ int retval;
+ char *newbase = malloc_base(base, path1, pathlen1);
+ if (opt->tree_in_recursive)
+ opt->change(opt, mode1, mode2,
+ sha1, sha2, base, path1);
+ retval = diff_tree_sha1(sha1, sha2, newbase, opt);
+ free(newbase);
+ return retval;
+ }
+
+ opt->change(opt, mode1, mode2, sha1, sha2, base, path1);
+ return 0;
+}
+
+static int interesting(struct tree_desc *desc, const char *base)
+{
+ const char *path;
+ unsigned mode;
+ int i;
+ int baselen, pathlen;
+
+ if (!nr_paths)
+ return 1;
+
+ (void)extract(desc, &path, &mode);
+
+ pathlen = strlen(path);
+ baselen = strlen(base);
+
+ for (i=0; i < nr_paths; i++) {
+ const char *match = paths[i];
+ int matchlen = pathlens[i];
+
+ if (baselen >= matchlen) {
+ /* If it doesn't match, move along... */
+ if (strncmp(base, match, matchlen))
+ continue;
+
+ /* The base is a subdirectory of a path which was specified. */
+ return 1;
+ }
+
+ /* Does the base match? */
+ if (strncmp(base, match, baselen))
+ continue;
+
+ match += baselen;
+ matchlen -= baselen;
+
+ if (pathlen > matchlen)
+ continue;
+
+ if (matchlen > pathlen) {
+ if (match[pathlen] != '/')
+ continue;
+ if (!S_ISDIR(mode))
+ continue;
+ }
+
+ if (strncmp(path, match, pathlen))
+ continue;
+
+ return 1;
+ }
+ return 0; /* No matches */
+}
+
+/* A whole sub-tree went away or appeared */
+static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)
+{
+ while (desc->size) {
+ if (interesting(desc, base))
+ show_entry(opt, prefix, desc, base);
+ update_tree_entry(desc);
+ }
+}
+
+/* A file entry went away or appeared */
+static int show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)
+{
+ unsigned mode;
+ const char *path;
+ const unsigned char *sha1 = extract(desc, &path, &mode);
+
+ if (opt->recursive && S_ISDIR(mode)) {
+ char type[20];
+ char *newbase = malloc_base(base, path, strlen(path));
+ struct tree_desc inner;
+ void *tree;
+
+ tree = read_sha1_file(sha1, type, &inner.size);
+ if (!tree || strcmp(type, "tree"))
+ die("corrupt tree sha %s", sha1_to_hex(sha1));
+
+ inner.buf = tree;
+ show_tree(opt, prefix, &inner, newbase);
+
+ free(tree);
+ free(newbase);
+ return 0;
+ }
+
+ opt->add_remove(opt, prefix[0], mode, sha1, base, path);
+ return 0;
+}
+
+int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
+{
+ while (t1->size | t2->size) {
+ if (nr_paths && t1->size && !interesting(t1, base)) {
+ update_tree_entry(t1);
+ continue;
+ }
+ if (nr_paths && t2->size && !interesting(t2, base)) {
+ update_tree_entry(t2);
+ continue;
+ }
+ if (!t1->size) {
+ show_entry(opt, "+", t2, base);
+ update_tree_entry(t2);
+ continue;
+ }
+ if (!t2->size) {
+ show_entry(opt, "-", t1, base);
+ update_tree_entry(t1);
+ continue;
+ }
+ switch (compare_tree_entry(t1, t2, base, opt)) {
+ case -1:
+ update_tree_entry(t1);
+ continue;
+ case 0:
+ update_tree_entry(t1);
+ /* Fallthrough */
+ case 1:
+ update_tree_entry(t2);
+ continue;
+ }
+ die("git-diff-tree: internal error");
+ }
+ return 0;
+}
+
+int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
+{
+ void *tree1, *tree2;
+ struct tree_desc t1, t2;
+ int retval;
+
+ tree1 = read_object_with_reference(old, "tree", &t1.size, NULL);
+ if (!tree1)
+ die("unable to read source tree (%s)", sha1_to_hex(old));
+ tree2 = read_object_with_reference(new, "tree", &t2.size, NULL);
+ if (!tree2)
+ die("unable to read destination tree (%s)", sha1_to_hex(new));
+ t1.buf = tree1;
+ t2.buf = tree2;
+ retval = diff_tree(&t1, &t2, base, opt);
+ free(tree1);
+ free(tree2);
+ return retval;
+}
+
+static int count_paths(const char **paths)
+{
+ int i = 0;
+ while (*paths++)
+ i++;
+ return i;
+}
+
+void diff_tree_setup_paths(const char **p)
+{
+ if (p) {
+ int i;
+
+ paths = p;
+ nr_paths = count_paths(paths);
+ pathlens = xmalloc(nr_paths * sizeof(int));
+ for (i=0; i<nr_paths; i++)
+ pathlens[i] = strlen(paths[i]);
+ }
+}