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>

diff --git a/Makefile b/Makefile
index 903c57cdaf2769b323f4da8a7de3eb5bb3f8cca9..7eacf61b3f79dd7786f0bb2389cde3854a811316 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -151,7 +151,7 @@ LIB_H = \
 
 DIFF_OBJS = \
        diff.o diffcore-break.o diffcore-order.o diffcore-pathspec.o \
-       diffcore-pickaxe.o diffcore-rename.o
+       diffcore-pickaxe.o diffcore-rename.o tree-diff.o
 
 LIB_OBJS = \
        blob.o commit.o connect.o count-delta.o csum-file.o \

diff --git a/diff-tree.c b/diff-tree.c
index 851722037df936c2b4e0ab6a9389291e74d5ae60..382011a2a6d1a701aeb1104991d9abbfcb5b73df 100644 (file)
--- a/diff-tree.c
+++ b/diff-tree.c
@@ -5,256 +5,13 @@
 static int show_root_diff = 0;
 static int verbose_header = 0;
 static int ignore_merges = 1;
-static int recursive = 0;
-static int show_tree_entry_in_recursive = 0;
 static int read_stdin = 0;
 
-static struct diff_options diff_options;
-
 static const char *header = NULL;
 static const char *header_prefix = "";
 static enum cmit_fmt commit_format = CMIT_FMT_RAW;
 
-// What paths are we interested in?
-static int nr_paths = 0;
-static const char **paths = NULL;
-static int *pathlens = NULL;
-
-static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base);
-
-static void update_tree_entry(void **bufp, unsigned long *sizep)
-{
-       void *buf = *bufp;
-       unsigned long size = *sizep;
-       int len = strlen(buf) + 1 + 20;
-
-       if (size < len)
-               die("corrupt tree file");
-       *bufp = buf + len;
-       *sizep = size - len;
-}
-
-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, ' ');
-       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 void show_file(const char *prefix, void *tree, unsigned long size, const char *base);
-static void show_tree(const char *prefix, void *tree, unsigned long size, const char *base);
-
-/* A file entry went away or appeared */
-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);
-
-       if (recursive && S_ISDIR(mode)) {
-               char type[20];
-               unsigned long size;
-               char *newbase = malloc_base(base, path, strlen(path));
-               void *tree;
-
-               tree = read_sha1_file(sha1, type, &size);
-               if (!tree || strcmp(type, "tree"))
-                       die("corrupt tree sha %s", sha1_to_hex(sha1));
-
-               show_tree(prefix, tree, size, newbase);
-
-               free(tree);
-               free(newbase);
-               return;
-       }
-
-       diff_addremove(&diff_options, prefix[0], mode, sha1, base, path);
-}
-
-static int compare_tree_entry(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
-{
-       unsigned mode1, mode2;
-       const char *path1, *path2;
-       const unsigned char *sha1, *sha2;
-       int cmp, pathlen1, pathlen2;
-
-       sha1 = extract(tree1, size1, &path1, &mode1);
-       sha2 = extract(tree2, size2, &path2, &mode2);
-
-       pathlen1 = strlen(path1);
-       pathlen2 = strlen(path2);
-       cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
-       if (cmp < 0) {
-               show_file("-", tree1, size1, base);
-               return -1;
-       }
-       if (cmp > 0) {
-               show_file("+", tree2, size2, base);
-               return 1;
-       }
-       if (!diff_options.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_file("-", tree1, size1, base);
-               show_file("+", tree2, size2, base);
-               return 0;
-       }
-
-       if (recursive && S_ISDIR(mode1)) {
-               int retval;
-               char *newbase = malloc_base(base, path1, pathlen1);
-               if (show_tree_entry_in_recursive)
-                       diff_change(&diff_options, mode1, mode2,
-                                   sha1, sha2, base, path1);
-               retval = diff_tree_sha1(sha1, sha2, newbase);
-               free(newbase);
-               return retval;
-       }
-
-       diff_change(&diff_options, mode1, mode2, sha1, sha2, base, path1);
-       return 0;
-}
-
-static int interesting(void *tree, unsigned long size, const char *base)
-{
-       const char *path;
-       unsigned mode;
-       int i;
-       int baselen, pathlen;
-
-       if (!nr_paths)
-               return 1;
-
-       (void)extract(tree, size, &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(const char *prefix, void *tree, unsigned long size, const char *base)
-{
-       while (size) {
-               if (interesting(tree, size, base))
-                       show_file(prefix, tree, size, base);
-               update_tree_entry(&tree, &size);
-       }
-}
-
-static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
-{
-       while (size1 | size2) {
-               if (nr_paths && size1 && !interesting(tree1, size1, base)) {
-                       update_tree_entry(&tree1, &size1);
-                       continue;
-               }
-               if (nr_paths && size2 && !interesting(tree2, size2, base)) {
-                       update_tree_entry(&tree2, &size2);
-                       continue;
-               }
-               if (!size1) {
-                       show_file("+", tree2, size2, base);
-                       update_tree_entry(&tree2, &size2);
-                       continue;
-               }
-               if (!size2) {
-                       show_file("-", tree1, size1, base);
-                       update_tree_entry(&tree1, &size1);
-                       continue;
-               }
-               switch (compare_tree_entry(tree1, size1, tree2, size2, base)) {
-               case -1:
-                       update_tree_entry(&tree1, &size1);
-                       continue;
-               case 0:
-                       update_tree_entry(&tree1, &size1);
-                       /* Fallthrough */
-               case 1:
-                       update_tree_entry(&tree2, &size2);
-                       continue;
-               }
-               die("git-diff-tree: internal error");
-       }
-       return 0;
-}
-
-static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base)
-{
-       void *tree1, *tree2;
-       unsigned long size1, size2;
-       int retval;
-
-       tree1 = read_object_with_reference(old, "tree", &size1, NULL);
-       if (!tree1)
-               die("unable to read source tree (%s)", sha1_to_hex(old));
-       tree2 = read_object_with_reference(new, "tree", &size2, NULL);
-       if (!tree2)
-               die("unable to read destination tree (%s)", sha1_to_hex(new));
-       retval = diff_tree(tree1, size1, tree2, size2, base);
-       free(tree1);
-       free(tree2);
-       return retval;
-}
+static struct diff_options diff_options;
 
 static void call_diff_setup_done(void)
 {
@@ -285,7 +42,7 @@ static int diff_tree_sha1_top(const unsigned char *old,
        int ret;
 
        call_diff_setup_done();
-       ret = diff_tree_sha1(old, new, base);
+       ret = diff_tree_sha1(old, new, base, &diff_options);
        call_diff_flush();
        return ret;
 }
@@ -294,13 +51,17 @@ static int diff_root_tree(const unsigned char *new, const char *base)
 {
        int retval;
        void *tree;
-       unsigned long size;
+       struct tree_desc empty, real;
 
        call_diff_setup_done();
-       tree = read_object_with_reference(new, "tree", &size, NULL);
+       tree = read_object_with_reference(new, "tree", &real.size, NULL);
        if (!tree)
                die("unable to read root tree (%s)", sha1_to_hex(new));
-       retval = diff_tree("", 0, tree, size, base);
+       real.buf = tree;
+
+       empty.buf = "";
+       empty.size = 0;
+       retval = diff_tree(&empty, &real, base, &diff_options);
        free(tree);
        call_diff_flush();
        return retval;
@@ -387,14 +148,6 @@ static int diff_tree_stdin(char *line)
        return diff_tree_commit(commit, line);
 }
 
-static int count_paths(const char **paths)
-{
-       int i = 0;
-       while (*paths++)
-               i++;
-       return i;
-}
-
 static const char diff_tree_usage[] =
 "git-diff-tree [--stdin] [-m] [-s] [-v] [--pretty] [-t] "
 "[<common diff options>] <tree-ish> <tree-ish>"
@@ -445,11 +198,12 @@ int main(int argc, const char **argv)
                        break;
                }
                if (!strcmp(arg, "-r")) {
-                       recursive = 1;
+                       diff_options.recursive = 1;
                        continue;
                }
                if (!strcmp(arg, "-t")) {
-                       recursive = show_tree_entry_in_recursive = 1;
+                       diff_options.recursive = 1;
+                       diff_options.tree_in_recursive = 1;
                        continue;
                }
                if (!strcmp(arg, "-m")) {
@@ -478,17 +232,9 @@ int main(int argc, const char **argv)
                usage(diff_tree_usage);
        }
        if (diff_options.output_format == DIFF_FORMAT_PATCH)
-               recursive = 1;
+               diff_options.recursive = 1;
 
-       paths = get_pathspec(prefix, argv);
-       if (paths) {
-               int i;
-
-               nr_paths = count_paths(paths);
-               pathlens = xmalloc(nr_paths * sizeof(int));
-               for (i=0; i<nr_paths; i++)
-                       pathlens[i] = strlen(paths[i]);
-       }
+       diff_tree_setup_paths(get_pathspec(prefix, argv));
 
        switch (nr_sha1) {
        case 0:

diff --git a/diff.c b/diff.c
index 306bcd9807803f37dd742ff5c479c4875c454e03..ec94a96a5d02fe4204cc69f03de2966264378f75 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -754,6 +754,9 @@ void diff_setup(struct diff_options *options)
        options->line_termination = '\n';
        options->break_opt = -1;
        options->rename_limit = -1;
+
+       options->change = diff_change;
+       options->add_remove = diff_addremove;
 }
 
 int diff_setup_done(struct diff_options *options)

diff --git a/diff.h b/diff.h
index 2f4a7b463b699e65848656279287e2d8e2048c16..51155479a46857ee03aa5f5e005abdad63db5495 100644 (file)
--- a/diff.h
+++ b/diff.h
@@ -8,11 +8,31 @@
        (S_ISREG(mode) ? (S_IFREG | ce_permissions(mode)) : \
        S_ISLNK(mode) ? S_IFLNK : S_IFDIR)
 
+struct tree_desc {
+       void *buf;
+       unsigned long size;
+};
+
+struct diff_options;
+
+typedef void (*change_fn_t)(struct diff_options *options,
+                unsigned old_mode, unsigned new_mode,
+                const unsigned char *old_sha1,
+                const unsigned char *new_sha1,
+                const char *base, const char *path);
+
+typedef void (*add_remove_fn_t)(struct diff_options *options,
+                   int addremove, unsigned mode,
+                   const unsigned char *sha1,
+                   const char *base, const char *path);
+
 struct diff_options {
        const char **paths;
        const char *filter;
        const char *orderfile;
        const char *pickaxe;
+       unsigned recursive:1,
+                tree_in_recursive:1;
        int break_opt;
        int detect_rename;
        int find_copies_harder;
@@ -23,8 +43,17 @@ struct diff_options {
        int reverse_diff;
        int rename_limit;
        int setup;
+
+       change_fn_t change;
+       add_remove_fn_t add_remove;
 };
 
+extern void diff_tree_setup_paths(const char **paths);
+extern int diff_tree(struct tree_desc *t1, struct tree_desc *t2,
+                    const char *base, struct diff_options *opt);
+extern int diff_tree_sha1(const unsigned char *old, const unsigned char *new,
+                         const char *base, struct diff_options *opt);
+
 extern void diff_addremove(struct diff_options *,
                           int addremove,
                           unsigned mode,

diff --git a/tree-diff.c b/tree-diff.c
new file mode 100644 (file)
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]);
+       }
+}