Fix up applymbox script for the addition of "git-" prefix
[gitweb.git] / diff.c
diff --git a/diff.c b/diff.c
index 32309971222bfd0647cb3885d9cf4903b7dfaacf..3cb41c533313fdd70b3f13858c68032aeb08062a 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -4,11 +4,16 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <signal.h>
-#include <limits.h>
 #include "cache.h"
+#include "quote.h"
 #include "diff.h"
+#include "diffcore.h"
 
 static const char *diff_opts = "-pu";
+static unsigned char null_sha1[20] = { 0, };
+
+static int reverse_diff;
+static int use_size_cache;
 
 static const char *external_diff(void)
 {
@@ -36,76 +41,123 @@ static const char *external_diff(void)
        return external_diff_cmd;
 }
 
-/* Help to copy the thing properly quoted for the shell safety.
- * any single quote is replaced with '\'', and the caller is
- * expected to enclose the result within a single quote pair.
- *
- * E.g.
- *  original     sq_expand     result
- *  name     ==> name      ==> 'name'
- *  a b      ==> a b       ==> 'a b'
- *  a'b      ==> a'\''b    ==> 'a'\''b'
- */
-static char *sq_expand(const char *src)
-{
-       static char *buf = NULL;
-       int cnt, c;
-       const char *cp;
-       char *bp;
-
-       /* count bytes needed to store the quoted string. */ 
-       for (cnt = 1, cp = src; *cp; cnt++, cp++)
-               if (*cp == '\'')
-                       cnt += 3;
-
-       buf = xmalloc(cnt);
-       bp = buf;
-       while ((c = *src++)) {
-               if (c != '\'')
-                       *bp++ = c;
-               else {
-                       bp = strcpy(bp, "'\\''");
-                       bp += 4;
-               }
-       }
-       *bp = 0;
-       return buf;
-}
-
 static struct diff_tempfile {
-       const char *name;
+       const char *name; /* filename external diff should read from */
        char hex[41];
        char mode[10];
        char tmp_path[50];
 } diff_temp[2];
 
-static void builtin_diff(const char *name,
-                        struct diff_tempfile *temp)
+static int count_lines(const char *filename)
 {
-       int i, next_at;
-       const char *diff_cmd = "diff -L'%s%s' -L'%s%s'";
-       const char *diff_arg  = "'%s' '%s'||:"; /* "||:" is to return 0 */
+       FILE *in;
+       int count, ch, completely_empty = 1, nl_just_seen = 0;
+       in = fopen(filename, "r");
+       count = 0;
+       while ((ch = fgetc(in)) != EOF)
+               if (ch == '\n') {
+                       count++;
+                       nl_just_seen = 1;
+                       completely_empty = 0;
+               }
+               else {
+                       nl_just_seen = 0;
+                       completely_empty = 0;
+               }
+       fclose(in);
+       if (completely_empty)
+               return 0;
+       if (!nl_just_seen)
+               count++; /* no trailing newline */
+       return count;
+}
+
+static void print_line_count(int count)
+{
+       switch (count) {
+       case 0:
+               printf("0,0");
+               break;
+       case 1:
+               printf("1");
+               break;
+       default:
+               printf("1,%d", count);
+               break;
+       }
+}
+
+static void copy_file(int prefix, const char *filename)
+{
+       FILE *in;
+       int ch, nl_just_seen = 1;
+       in = fopen(filename, "r");
+       while ((ch = fgetc(in)) != EOF) {
+               if (nl_just_seen)
+                       putchar(prefix);
+               putchar(ch);
+               if (ch == '\n')
+                       nl_just_seen = 1;
+               else
+                       nl_just_seen = 0;
+       }
+       fclose(in);
+       if (!nl_just_seen)
+               printf("\n\\ No newline at end of file\n");
+}
+
+static void emit_rewrite_diff(const char *name_a,
+                             const char *name_b,
+                             struct diff_tempfile *temp)
+{
+       /* Use temp[i].name as input, name_a and name_b as labels */
+       int lc_a, lc_b;
+       lc_a = count_lines(temp[0].name);
+       lc_b = count_lines(temp[1].name);
+       printf("--- %s\n+++ %s\n@@ -", name_a, name_b);
+       print_line_count(lc_a);
+       printf(" +");
+       print_line_count(lc_b);
+       printf(" @@\n");
+       if (lc_a)
+               copy_file('-', temp[0].name);
+       if (lc_b)
+               copy_file('+', temp[1].name);
+}
+
+static void builtin_diff(const char *name_a,
+                        const char *name_b,
+                        struct diff_tempfile *temp,
+                        const char *xfrm_msg,
+                        int complete_rewrite)
+{
+       int i, next_at, cmd_size;
+       const char *diff_cmd = "diff -L%s%s -L%s%s";
+       const char *diff_arg  = "%s %s||:"; /* "||:" is to return 0 */
        const char *input_name_sq[2];
        const char *path0[2];
        const char *path1[2];
-       const char *name_sq = sq_expand(name);
+       const char *name_sq[2];
        char *cmd;
-       
+
+       name_sq[0] = sq_quote(name_a);
+       name_sq[1] = sq_quote(name_b);
+
        /* diff_cmd and diff_arg have 6 %s in total which makes
         * the sum of these strings 12 bytes larger than required.
         * we use 2 spaces around diff-opts, and we need to count
         * terminating NUL, so we subtract 9 here.
         */
-       int cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
+       cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
                        strlen(diff_arg) - 9);
        for (i = 0; i < 2; i++) {
-               input_name_sq[i] = sq_expand(temp[i].name);
+               input_name_sq[i] = sq_quote(temp[i].name);
                if (!strcmp(temp[i].name, "/dev/null")) {
                        path0[i] = "/dev/null";
                        path1[i] = "";
                } else {
                        path0[i] = i ? "b/" : "a/";
-                       path1[i] = name_sq;
+                       path1[i] = name_sq[i];
                }
                cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
                             strlen(input_name_sq[i]));
@@ -122,24 +174,64 @@ static void builtin_diff(const char *name,
        next_at += snprintf(cmd+next_at, cmd_size-next_at,
                            diff_arg, input_name_sq[0], input_name_sq[1]);
 
-       if (!path1[0][0])
-               printf("Created: %s (mode:%s)\n", name, temp[1].mode);
-       else if (!path1[1][0])
-               printf("Deleted: %s\n", name);
-       else if (strcmp(temp[0].mode, temp[1].mode)) {
-               printf("Mode changed: %s (%s->%s)\n", name,
-                      temp[0].mode, temp[1].mode);
-               /* Be careful.  We do not want to diff between
-                * symlink and a file.
-                */
-               if (strncmp(temp[0].mode, "120", 3) !=
-                   strncmp(temp[1].mode, "120", 3))
+       printf("diff --git a/%s b/%s\n", name_a, name_b);
+       if (!path1[0][0]) {
+               printf("new file mode %s\n", temp[1].mode);
+               if (xfrm_msg && xfrm_msg[0])
+                       puts(xfrm_msg);
+       }
+       else if (!path1[1][0]) {
+               printf("deleted file mode %s\n", temp[0].mode);
+               if (xfrm_msg && xfrm_msg[0])
+                       puts(xfrm_msg);
+       }
+       else {
+               if (strcmp(temp[0].mode, temp[1].mode)) {
+                       printf("old mode %s\n", temp[0].mode);
+                       printf("new mode %s\n", temp[1].mode);
+               }
+               if (xfrm_msg && xfrm_msg[0])
+                       puts(xfrm_msg);
+               if (strncmp(temp[0].mode, temp[1].mode, 3))
+                       /* we do not run diff between different kind
+                        * of objects.
+                        */
+                       exit(0);
+               if (complete_rewrite) {
+                       fflush(NULL);
+                       emit_rewrite_diff(name_a, name_b, temp);
                        exit(0);
+               }
        }
        fflush(NULL);
        execlp("/bin/sh","sh", "-c", cmd, NULL);
 }
 
+struct diff_filespec *alloc_filespec(const char *path)
+{
+       int namelen = strlen(path);
+       struct diff_filespec *spec = xmalloc(sizeof(*spec) + namelen + 1);
+       spec->path = (char *)(spec + 1);
+       strcpy(spec->path, path);
+       spec->should_free = spec->should_munmap = 0;
+       spec->xfrm_flags = 0;
+       spec->size = 0;
+       spec->data = NULL;
+       spec->mode = 0;
+       memset(spec->sha1, 0, 20);
+       return spec;
+}
+
+void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
+                  unsigned short mode)
+{
+       if (mode) {
+               spec->mode = DIFF_FILE_CANON_MODE(mode);
+               memcpy(spec->sha1, sha1, 20);
+               spec->sha1_valid = !!memcmp(sha1, null_sha1, 20);
+       }
+}
+
 /*
  * Given a name and sha1 pair, if the dircache tells us the file in
  * the work tree has that object contents, return true, so that
@@ -150,19 +242,19 @@ static int work_tree_matches(const char *name, const unsigned char *sha1)
        struct cache_entry *ce;
        struct stat st;
        int pos, len;
-       
+
        /* We do not read the cache ourselves here, because the
         * benchmark with my previous version that always reads cache
         * shows that it makes things worse for diff-tree comparing
         * two linux-2.6 kernel trees in an already checked out work
-        * tree.  This is because most diff-tree comparison deals with
+        * tree.  This is because most diff-tree comparisons deal with
         * only a small number of files, while reading the cache is
         * expensive for a large project, and its cost outweighs the
         * savings we get by not inflating the object to a temporary
         * file.  Practically, this code only helps when we are used
         * by diff-cache --cached, which does read the cache before
         * calling us.
-        */ 
+        */
        if (!active_cache)
                return 0;
 
@@ -172,13 +264,153 @@ static int work_tree_matches(const char *name, const unsigned char *sha1)
                return 0;
        ce = active_cache[pos];
        if ((lstat(name, &st) < 0) ||
-           !S_ISREG(st.st_mode) ||
-           cache_match_stat(ce, &st) ||
+           !S_ISREG(st.st_mode) || /* careful! */
+           ce_match_stat(ce, &st) ||
            memcmp(sha1, ce->sha1, 20))
                return 0;
+       /* we return 1 only when we can stat, it is a regular file,
+        * stat information matches, and sha1 recorded in the cache
+        * matches.  I.e. we know the file in the work tree really is
+        * the same as the <name, sha1> pair.
+        */
        return 1;
 }
 
+static struct sha1_size_cache {
+       unsigned char sha1[20];
+       unsigned long size;
+} **sha1_size_cache;
+static int sha1_size_cache_nr, sha1_size_cache_alloc;
+
+static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
+                                                int find_only,
+                                                unsigned long size)
+{
+       int first, last;
+       struct sha1_size_cache *e;
+
+       first = 0;
+       last = sha1_size_cache_nr;
+       while (last > first) {
+               int cmp, next = (last + first) >> 1;
+               e = sha1_size_cache[next];
+               cmp = memcmp(e->sha1, sha1, 20);
+               if (!cmp)
+                       return e;
+               if (cmp < 0) {
+                       last = next;
+                       continue;
+               }
+               first = next+1;
+       }
+       /* not found */
+       if (find_only)
+               return NULL;
+       /* insert to make it at "first" */
+       if (sha1_size_cache_alloc <= sha1_size_cache_nr) {
+               sha1_size_cache_alloc = alloc_nr(sha1_size_cache_alloc);
+               sha1_size_cache = xrealloc(sha1_size_cache,
+                                          sha1_size_cache_alloc *
+                                          sizeof(*sha1_size_cache));
+       }
+       sha1_size_cache_nr++;
+       if (first < sha1_size_cache_nr)
+               memmove(sha1_size_cache + first + 1, sha1_size_cache + first,
+                       (sha1_size_cache_nr - first - 1) *
+                       sizeof(*sha1_size_cache));
+       e = xmalloc(sizeof(struct sha1_size_cache));
+       sha1_size_cache[first] = e;
+       memcpy(e->sha1, sha1, 20);
+       e->size = size;
+       return e;
+}
+
+/*
+ * While doing rename detection and pickaxe operation, we may need to
+ * grab the data for the blob (or file) for our own in-core comparison.
+ * diff_filespec has data and size fields for this purpose.
+ */
+int diff_populate_filespec(struct diff_filespec *s, int size_only)
+{
+       int err = 0;
+       if (!DIFF_FILE_VALID(s))
+               die("internal error: asking to populate invalid file.");
+       if (S_ISDIR(s->mode))
+               return -1;
+
+       if (!use_size_cache)
+               size_only = 0;
+
+       if (s->data)
+               return err;
+       if (!s->sha1_valid ||
+           work_tree_matches(s->path, s->sha1)) {
+               struct stat st;
+               int fd;
+               if (lstat(s->path, &st) < 0) {
+                       if (errno == ENOENT) {
+                       err_empty:
+                               err = -1;
+                       empty:
+                               s->data = "";
+                               s->size = 0;
+                               return err;
+                       }
+               }
+               s->size = st.st_size;
+               if (!s->size)
+                       goto empty;
+               if (size_only)
+                       return 0;
+               if (S_ISLNK(st.st_mode)) {
+                       int ret;
+                       s->data = xmalloc(s->size);
+                       s->should_free = 1;
+                       ret = readlink(s->path, s->data, s->size);
+                       if (ret < 0) {
+                               free(s->data);
+                               goto err_empty;
+                       }
+                       return 0;
+               }
+               fd = open(s->path, O_RDONLY);
+               if (fd < 0)
+                       goto err_empty;
+               s->data = mmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
+               s->should_munmap = 1;
+               close(fd);
+       }
+       else {
+               char type[20];
+               struct sha1_size_cache *e;
+
+               if (size_only) {
+                       e = locate_size_cache(s->sha1, 1, 0);
+                       if (e) {
+                               s->size = e->size;
+                               return 0;
+                       }
+                       if (!sha1_object_info(s->sha1, type, &s->size))
+                               locate_size_cache(s->sha1, 0, s->size);
+               }
+               else {
+                       s->data = read_sha1_file(s->sha1, type, &s->size);
+                       s->should_free = 1;
+               }
+       }
+       return 0;
+}
+
+void diff_free_filespec_data(struct diff_filespec *s)
+{
+       if (s->should_free)
+               free(s->data);
+       else if (s->should_munmap)
+               munmap(s->data, s->size);
+       s->should_free = s->should_munmap = 0;
+       s->data = NULL;
+}
+
 static void prep_temp_blob(struct diff_tempfile *temp,
                           void *blob,
                           unsigned long size,
@@ -202,12 +434,9 @@ static void prep_temp_blob(struct diff_tempfile *temp,
 
 static void prepare_temp_file(const char *name,
                              struct diff_tempfile *temp,
-                             struct diff_spec *one)
+                             struct diff_filespec *one)
 {
-       static unsigned char null_sha1[20] = { 0, };
-       int use_work_tree = 0;
-
-       if (!one->file_valid) {
+       if (!DIFF_FILE_VALID(one)) {
        not_a_valid_file:
                /* A '-' entry produces this for file-2, and
                 * a '+' entry produces this for file-1.
@@ -218,18 +447,13 @@ static void prepare_temp_file(const char *name,
                return;
        }
 
-       if (one->sha1_valid &&
-           (!memcmp(one->blob_sha1, null_sha1, sizeof(null_sha1)) ||
-            work_tree_matches(name, one->blob_sha1)))
-               use_work_tree = 1;
-
-       if (!one->sha1_valid || use_work_tree) {
+       if (!one->sha1_valid ||
+           work_tree_matches(name, one->sha1)) {
                struct stat st;
-               temp->name = name;
-               if (lstat(temp->name, &st) < 0) {
+               if (lstat(name, &st) < 0) {
                        if (errno == ENOENT)
                                goto not_a_valid_file;
-                       die("stat(%s): %s", temp->name, strerror(errno));
+                       die("stat(%s): %s", name, strerror(errno));
                }
                if (S_ISLNK(st.st_mode)) {
                        int ret;
@@ -241,31 +465,32 @@ static void prepare_temp_file(const char *name,
                                die("readlink(%s)", name);
                        prep_temp_blob(temp, buf, st.st_size,
                                       (one->sha1_valid ?
-                                       one->blob_sha1 : null_sha1),
+                                       one->sha1 : null_sha1),
                                       (one->sha1_valid ?
                                        one->mode : S_IFLNK));
                }
                else {
+                       /* we can borrow from the file in the work tree */
+                       temp->name = name;
                        if (!one->sha1_valid)
                                strcpy(temp->hex, sha1_to_hex(null_sha1));
                        else
-                               strcpy(temp->hex, sha1_to_hex(one->blob_sha1));
-                       sprintf(temp->mode, "%06o",
-                               S_IFREG |ce_permissions(st.st_mode));
+                               strcpy(temp->hex, sha1_to_hex(one->sha1));
+                       /* Even though we may sometimes borrow the
+                        * contents from the work tree, we always want
+                        * one->mode.  mode is trustworthy even when
+                        * !(one->sha1_valid), as long as
+                        * DIFF_FILE_VALID(one).
+                        */
+                       sprintf(temp->mode, "%06o", one->mode);
                }
                return;
        }
        else {
-               void *blob;
-               char type[20];
-               unsigned long size;
-
-               blob = read_sha1_file(one->blob_sha1, type, &size);
-               if (!blob || strcmp(type, "blob"))
-                       die("unable to read blob object for %s (%s)",
-                           name, sha1_to_hex(one->blob_sha1));
-               prep_temp_blob(temp, blob, size, one->blob_sha1, one->mode);
-               free(blob);
+               if (diff_populate_filespec(one, 0))
+                       die("cannot read data blob for %s", one->path);
+               prep_temp_blob(temp, one->data, one->size,
+                              one->sha1, one->mode);
        }
 }
 
@@ -288,12 +513,16 @@ static void remove_tempfile_on_signal(int signo)
 /* An external diff command takes:
  *
  * diff-cmd name infile1 infile1-sha1 infile1-mode \
- *               infile2 infile2-sha1 infile2-mode.
+ *               infile2 infile2-sha1 infile2-mode [ rename-to ]
  *
  */
-void run_external_diff(const char *name,
-                      struct diff_spec *one,
-                      struct diff_spec *two)
+static void run_external_diff(const char *pgm,
+                             const char *name,
+                             const char *other,
+                             struct diff_filespec *one,
+                             struct diff_filespec *two,
+                             const char *xfrm_msg,
+                             int complete_rewrite)
 {
        struct diff_tempfile *temp = diff_temp;
        pid_t pid;
@@ -302,7 +531,7 @@ void run_external_diff(const char *name,
 
        if (one && two) {
                prepare_temp_file(name, &temp[0], one);
-               prepare_temp_file(name, &temp[1], two);
+               prepare_temp_file(other ? : name, &temp[1], two);
                if (! atexit_asked &&
                    (temp[0].name == temp[0].tmp_path ||
                     temp[1].name == temp[1].tmp_path)) {
@@ -317,14 +546,25 @@ void run_external_diff(const char *name,
        if (pid < 0)
                die("unable to fork");
        if (!pid) {
-               const char *pgm = external_diff();
                if (pgm) {
-                       if (one && two)
-                               execlp(pgm, pgm,
-                                      name,
-                                      temp[0].name, temp[0].hex, temp[0].mode,
-                                      temp[1].name, temp[1].hex, temp[1].mode,
-                                      NULL);
+                       if (one && two) {
+                               const char *exec_arg[10];
+                               const char **arg = &exec_arg[0];
+                               *arg++ = pgm;
+                               *arg++ = name;
+                               *arg++ = temp[0].name;
+                               *arg++ = temp[0].hex;
+                               *arg++ = temp[0].mode;
+                               *arg++ = temp[1].name;
+                               *arg++ = temp[1].hex;
+                               *arg++ = temp[1].mode;
+                               if (other) {
+                                       *arg++ = other;
+                                       *arg++ = xfrm_msg;
+                               }
+                               *arg = NULL;
+                               execvp(pgm, (char *const*) exec_arg);
+                       }
                        else
                                execlp(pgm, pgm, name, NULL);
                }
@@ -332,7 +572,8 @@ void run_external_diff(const char *name,
                 * otherwise we use the built-in one.
                 */
                if (one && two)
-                       builtin_diff(name, temp);
+                       builtin_diff(name, other ? : name, temp, xfrm_msg,
+                                    complete_rewrite);
                else
                        printf("* Unmerged path %s\n", name);
                exit(0);
@@ -355,53 +596,598 @@ void run_external_diff(const char *name,
        remove_tempfile();
 }
 
+static void run_diff(struct diff_filepair *p)
+{
+       const char *pgm = external_diff();
+       char msg_[PATH_MAX*2+200], *xfrm_msg;
+       struct diff_filespec *one;
+       struct diff_filespec *two;
+       const char *name;
+       const char *other;
+       int complete_rewrite = 0;
+
+       if (DIFF_PAIR_UNMERGED(p)) {
+               /* unmerged */
+               run_external_diff(pgm, p->one->path, NULL, NULL, NULL, NULL,
+                                 0);
+               return;
+       }
+
+       name = p->one->path;
+       other = (strcmp(name, p->two->path) ? p->two->path : NULL);
+       one = p->one; two = p->two;
+       switch (p->status) {
+       case 'C':
+               sprintf(msg_,
+                       "similarity index %d%%\n"
+                       "copy from %s\n"
+                       "copy to %s",
+                       (int)(0.5 + p->score * 100.0/MAX_SCORE),
+                       name, other);
+               xfrm_msg = msg_;
+               break;
+       case 'R':
+               sprintf(msg_,
+                       "similarity index %d%%\n"
+                       "rename from %s\n"
+                       "rename to %s",
+                       (int)(0.5 + p->score * 100.0/MAX_SCORE),
+                       name, other);
+               xfrm_msg = msg_;
+               break;
+       case 'M':
+               if (p->score) {
+                       sprintf(msg_,
+                               "dissimilarity index %d%%",
+                               (int)(0.5 + p->score * 100.0/MAX_SCORE));
+                       xfrm_msg = msg_;
+                       complete_rewrite = 1;
+                       break;
+               }
+               /* fallthru */
+       default:
+               xfrm_msg = NULL;
+       }
+
+       if (!pgm &&
+           DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
+           (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
+               /* a filepair that changes between file and symlink
+                * needs to be split into deletion and creation.
+                */
+               struct diff_filespec *null = alloc_filespec(two->path);
+               run_external_diff(NULL, name, other, one, null, xfrm_msg, 0);
+               free(null);
+               null = alloc_filespec(one->path);
+               run_external_diff(NULL, name, other, null, two, xfrm_msg, 0);
+               free(null);
+       }
+       else
+               run_external_diff(pgm, name, other, one, two, xfrm_msg,
+                                 complete_rewrite);
+}
+
+void diff_setup(int flags)
+{
+       if (flags & DIFF_SETUP_REVERSE)
+               reverse_diff = 1;
+       if (flags & DIFF_SETUP_USE_CACHE) {
+               if (!active_cache)
+                       /* read-cache does not die even when it fails
+                        * so it is safe for us to do this here.  Also
+                        * it does not smudge active_cache or active_nr
+                        * when it fails, so we do not have to worry about
+                        * cleaning it up oufselves either.
+                        */
+                       read_cache();
+       }
+       if (flags & DIFF_SETUP_USE_SIZE_CACHE)
+               use_size_cache = 1;
+       
+}
+
+static int parse_num(const char **cp_p)
+{
+       int num, scale, ch, cnt;
+       const char *cp = *cp_p;
+
+       cnt = num = 0;
+       scale = 1;
+       while ('0' <= (ch = *cp) && ch <= '9') {
+               if (cnt++ < 5) {
+                       /* We simply ignore more than 5 digits precision. */
+                       scale *= 10;
+                       num = num * 10 + ch - '0';
+               }
+               *cp++;
+       }
+       *cp_p = cp;
+
+       /* user says num divided by scale and we say internally that
+        * is MAX_SCORE * num / scale.
+        */
+       return (MAX_SCORE * num / scale);
+}
+
+int diff_scoreopt_parse(const char *opt)
+{
+       int opt1, opt2, cmd;
+
+       if (*opt++ != '-')
+               return -1;
+       cmd = *opt++;
+       if (cmd != 'M' && cmd != 'C' && cmd != 'B')
+               return -1; /* that is not a -M, -C nor -B option */
+
+       opt1 = parse_num(&opt);
+       if (cmd != 'B')
+               opt2 = 0;
+       else {
+               if (*opt == 0)
+                       opt2 = 0;
+               else if (*opt != '/')
+                       return -1; /* we expect -B80/99 or -B80 */
+               else {
+                       opt++;
+                       opt2 = parse_num(&opt);
+               }
+       }
+       if (*opt != 0)
+               return -1;
+       return opt1 | (opt2 << 16);
+}
+
+struct diff_queue_struct diff_queued_diff;
+
+void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
+{
+       if (queue->alloc <= queue->nr) {
+               queue->alloc = alloc_nr(queue->alloc);
+               queue->queue = xrealloc(queue->queue,
+                                       sizeof(dp) * queue->alloc);
+       }
+       queue->queue[queue->nr++] = dp;
+}
+
+struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
+                                struct diff_filespec *one,
+                                struct diff_filespec *two)
+{
+       struct diff_filepair *dp = xmalloc(sizeof(*dp));
+       dp->one = one;
+       dp->two = two;
+       dp->score = 0;
+       dp->status = 0;
+       dp->source_stays = 0;
+       dp->broken_pair = 0;
+       diff_q(queue, dp);
+       return dp;
+}
+
+void diff_free_filepair(struct diff_filepair *p)
+{
+       diff_free_filespec_data(p->one);
+       diff_free_filespec_data(p->two);
+       free(p);
+}
+
+static void diff_flush_raw(struct diff_filepair *p,
+                          int line_termination,
+                          int inter_name_termination)
+{
+       int two_paths;
+       char status[10];
+
+       if (line_termination) {
+               const char *err = "path %s cannot be expressed without -z";
+               if (strchr(p->one->path, line_termination) ||
+                   strchr(p->one->path, inter_name_termination))
+                       die(err, p->one->path);
+               if (strchr(p->two->path, line_termination) ||
+                   strchr(p->two->path, inter_name_termination))
+                       die(err, p->two->path);
+       }
+
+       if (p->score)
+               sprintf(status, "%c%03d", p->status,
+                       (int)(0.5 + p->score * 100.0/MAX_SCORE));
+       else {
+               status[0] = p->status;
+               status[1] = 0;
+       }
+       switch (p->status) {
+       case 'C': case 'R':
+               two_paths = 1;
+               break;
+       case 'N': case 'D':
+               two_paths = 0;
+               break;
+       default:
+               two_paths = 0;
+               break;
+       }
+       printf(":%06o %06o %s ",
+              p->one->mode, p->two->mode, sha1_to_hex(p->one->sha1));
+       printf("%s %s%c%s",
+              sha1_to_hex(p->two->sha1),
+              status,
+              inter_name_termination,
+              p->one->path);
+       if (two_paths)
+               printf("%c%s", inter_name_termination, p->two->path);
+       putchar(line_termination);
+}
+
+static void diff_flush_name(struct diff_filepair *p,
+                           int line_termination)
+{
+       printf("%s%c", p->two->path, line_termination);
+}
+
+int diff_unmodified_pair(struct diff_filepair *p)
+{
+       /* This function is written stricter than necessary to support
+        * the currently implemented transformers, but the idea is to
+        * let transformers to produce diff_filepairs any way they want,
+        * and filter and clean them up here before producing the output.
+        */
+       struct diff_filespec *one, *two;
+
+       if (DIFF_PAIR_UNMERGED(p))
+               return 0; /* unmerged is interesting */
+
+       one = p->one;
+       two = p->two;
+
+       /* deletion, addition, mode or type change
+        * and rename are all interesting.
+        */
+       if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
+           DIFF_PAIR_MODE_CHANGED(p) ||
+           strcmp(one->path, two->path))
+               return 0;
+
+       /* both are valid and point at the same path.  that is, we are
+        * dealing with a change.
+        */
+       if (one->sha1_valid && two->sha1_valid &&
+           !memcmp(one->sha1, two->sha1, sizeof(one->sha1)))
+               return 1; /* no change */
+       if (!one->sha1_valid && !two->sha1_valid)
+               return 1; /* both look at the same file on the filesystem. */
+       return 0;
+}
+
+static void diff_flush_patch(struct diff_filepair *p)
+{
+       if (diff_unmodified_pair(p))
+               return;
+
+       if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
+           (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
+               return; /* no tree diffs in patch format */ 
+
+       run_diff(p);
+}
+
+int diff_queue_is_empty(void)
+{
+       struct diff_queue_struct *q = &diff_queued_diff;
+       int i;
+       for (i = 0; i < q->nr; i++)
+               if (!diff_unmodified_pair(q->queue[i]))
+                       return 0;
+       return 1;
+}
+
+#if DIFF_DEBUG
+void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
+{
+       fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
+               x, one ? : "",
+               s->path,
+               DIFF_FILE_VALID(s) ? "valid" : "invalid",
+               s->mode,
+               s->sha1_valid ? sha1_to_hex(s->sha1) : "");
+       fprintf(stderr, "queue[%d] %s size %lu flags %d\n",
+               x, one ? : "",
+               s->size, s->xfrm_flags);
+}
+
+void diff_debug_filepair(const struct diff_filepair *p, int i)
+{
+       diff_debug_filespec(p->one, i, "one");
+       diff_debug_filespec(p->two, i, "two");
+       fprintf(stderr, "score %d, status %c stays %d broken %d\n",
+               p->score, p->status ? : '?',
+               p->source_stays, p->broken_pair);
+}
+
+void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
+{
+       int i;
+       if (msg)
+               fprintf(stderr, "%s\n", msg);
+       fprintf(stderr, "q->nr = %d\n", q->nr);
+       for (i = 0; i < q->nr; i++) {
+               struct diff_filepair *p = q->queue[i];
+               diff_debug_filepair(p, i);
+       }
+}
+#endif
+
+static void diff_resolve_rename_copy(void)
+{
+       int i, j;
+       struct diff_filepair *p, *pp;
+       struct diff_queue_struct *q = &diff_queued_diff;
+
+       diff_debug_queue("resolve-rename-copy", q);
+
+       for (i = 0; i < q->nr; i++) {
+               p = q->queue[i];
+               p->status = 0; /* undecided */
+               if (DIFF_PAIR_UNMERGED(p))
+                       p->status = 'U';
+               else if (!DIFF_FILE_VALID(p->one))
+                       p->status = 'N';
+               else if (!DIFF_FILE_VALID(p->two))
+                       p->status = 'D';
+               else if (DIFF_PAIR_TYPE_CHANGED(p))
+                       p->status = 'T';
+
+               /* from this point on, we are dealing with a pair
+                * whose both sides are valid and of the same type, i.e.
+                * either in-place edit or rename/copy edit.
+                */
+               else if (DIFF_PAIR_RENAME(p)) {
+                       if (p->source_stays) {
+                               p->status = 'C';
+                               continue;
+                       }
+                       /* See if there is some other filepair that
+                        * copies from the same source as us.  If so
+                        * we are a copy.  Otherwise we are a rename.
+                        */
+                       for (j = i + 1; j < q->nr; j++) {
+                               pp = q->queue[j];
+                               if (strcmp(pp->one->path, p->one->path))
+                                       continue; /* not us */
+                               if (!DIFF_PAIR_RENAME(pp))
+                                       continue; /* not a rename/copy */
+                               /* pp is a rename/copy from the same source */
+                               p->status = 'C';
+                               break;
+                       }
+                       if (!p->status)
+                               p->status = 'R';
+               }
+               else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
+                        p->one->mode != p->two->mode)
+                       p->status = 'M';
+               else {
+                       /* This is a "no-change" entry and should not
+                        * happen anymore, but prepare for broken callers.
+                        */
+                       error("feeding unmodified %s to diffcore",
+                             p->one->path);
+                       p->status = 'X';
+               }
+       }
+       diff_debug_queue("resolve-rename-copy done", q);
+}
+
+void diff_flush(int diff_output_style, int line_termination)
+{
+       struct diff_queue_struct *q = &diff_queued_diff;
+       int i;
+       int inter_name_termination = '\t';
+
+       if (!line_termination)
+               inter_name_termination = 0;
+
+       for (i = 0; i < q->nr; i++) {
+               struct diff_filepair *p = q->queue[i];
+               if ((diff_output_style == DIFF_FORMAT_NO_OUTPUT) ||
+                   (p->status == 'X'))
+                       continue;
+               if (p->status == 0)
+                       die("internal error in diff-resolve-rename-copy");
+               switch (diff_output_style) {
+               case DIFF_FORMAT_PATCH:
+                       diff_flush_patch(p);
+                       break;
+               case DIFF_FORMAT_RAW:
+                       diff_flush_raw(p, line_termination,
+                                      inter_name_termination);
+                       break;
+               case DIFF_FORMAT_NAME:
+                       diff_flush_name(p, line_termination);
+                       break;
+               }
+       }
+       for (i = 0; i < q->nr; i++)
+               diff_free_filepair(q->queue[i]);
+       free(q->queue);
+       q->queue = NULL;
+       q->nr = q->alloc = 0;
+}
+
+static void diffcore_apply_filter(const char *filter)
+{
+       int i;
+       struct diff_queue_struct *q = &diff_queued_diff;
+       struct diff_queue_struct outq;
+       outq.queue = NULL;
+       outq.nr = outq.alloc = 0;
+
+       if (!filter)
+               return;
+
+       if (strchr(filter, 'A')) {
+               /* All-or-none */
+               int found;
+               for (i = found = 0; !found && i < q->nr; i++) {
+                       struct diff_filepair *p = q->queue[i];
+                       if (((p->status == 'M') &&
+                            ((p->score && strchr(filter, 'B')) ||
+                             (!p->score && strchr(filter, 'M')))) ||
+                           ((p->status != 'M') && strchr(filter, p->status)))
+                               found++;
+               }
+               if (found)
+                       return;
+
+               /* otherwise we will clear the whole queue
+                * by copying the empty outq at the end of this
+                * function, but first clear the current entries
+                * in the queue.
+                */
+               for (i = 0; i < q->nr; i++)
+                       diff_free_filepair(q->queue[i]);
+       }
+       else {
+               /* Only the matching ones */
+               for (i = 0; i < q->nr; i++) {
+                       struct diff_filepair *p = q->queue[i];
+                       if (((p->status == 'M') &&
+                            ((p->score && strchr(filter, 'B')) ||
+                             (!p->score && strchr(filter, 'M')))) ||
+                           ((p->status != 'M') && strchr(filter, p->status)))
+                               diff_q(&outq, p);
+                       else
+                               diff_free_filepair(p);
+               }
+       }
+       free(q->queue);
+       *q = outq;
+}
+
+void diffcore_std(const char **paths,
+                 int detect_rename, int rename_score,
+                 const char *pickaxe, int pickaxe_opts,
+                 int break_opt,
+                 const char *orderfile,
+                 const char *filter)
+{
+       if (paths && paths[0])
+               diffcore_pathspec(paths);
+       if (break_opt != -1)
+               diffcore_break(break_opt);
+       if (detect_rename)
+               diffcore_rename(detect_rename, rename_score);
+       if (break_opt != -1)
+               diffcore_merge_broken();
+       if (pickaxe)
+               diffcore_pickaxe(pickaxe, pickaxe_opts);
+       if (orderfile)
+               diffcore_order(orderfile);
+       diff_resolve_rename_copy();
+       diffcore_apply_filter(filter);
+}
+
+
+void diffcore_std_no_resolve(const char **paths,
+                            const char *pickaxe, int pickaxe_opts,
+                            const char *orderfile,
+                            const char *filter)
+{
+       if (paths && paths[0])
+               diffcore_pathspec(paths);
+       if (pickaxe)
+               diffcore_pickaxe(pickaxe, pickaxe_opts);
+       if (orderfile)
+               diffcore_order(orderfile);
+       diffcore_apply_filter(filter);
+}
+
 void diff_addremove(int addremove, unsigned mode,
                    const unsigned char *sha1,
                    const char *base, const char *path)
 {
        char concatpath[PATH_MAX];
-       struct diff_spec spec[2], *one, *two;
+       struct diff_filespec *one, *two;
 
-       memcpy(spec[0].blob_sha1, sha1, 20);
-       spec[0].mode = mode;
-       spec[0].sha1_valid = spec[0].file_valid = 1;
-       spec[1].file_valid = 0;
+       /* This may look odd, but it is a preparation for
+        * feeding "there are unchanged files which should
+        * not produce diffs, but when you are doing copy
+        * detection you would need them, so here they are"
+        * entries to the diff-core.  They will be prefixed
+        * with something like '=' or '*' (I haven't decided
+        * which but should not make any difference).
+        * Feeding the same new and old to diff_change() 
+        * also has the same effect.
+        * Before the final output happens, they are pruned after
+        * merged into rename/copy pairs as appropriate.
+        */
+       if (reverse_diff)
+               addremove = (addremove == '+' ? '-' :
+                            addremove == '-' ? '+' : addremove);
 
-       if (addremove == '+') {
-               one = spec + 1; two = spec;
-       } else {
-               one = spec; two = one + 1;
-       }
-       
-       if (path) {
-               strcpy(concatpath, base);
-               strcat(concatpath, path);
-       }
-       run_external_diff(path ? concatpath : base, one, two);
+       if (!path) path = "";
+       sprintf(concatpath, "%s%s", base, path);
+       one = alloc_filespec(concatpath);
+       two = alloc_filespec(concatpath);
+
+       if (addremove != '+')
+               fill_filespec(one, sha1, mode);
+       if (addremove != '-')
+               fill_filespec(two, sha1, mode);
+
+       diff_queue(&diff_queued_diff, one, two);
+}
+
+void diff_helper_input(unsigned old_mode,
+                      unsigned new_mode,
+                      const unsigned char *old_sha1,
+                      const unsigned char *new_sha1,
+                      const char *old_path,
+                      int status,
+                      int score,
+                      const char *new_path)
+{
+       struct diff_filespec *one, *two;
+       struct diff_filepair *dp;
+
+       one = alloc_filespec(old_path);
+       two = alloc_filespec(new_path);
+       if (old_mode)
+               fill_filespec(one, old_sha1, old_mode);
+       if (new_mode)
+               fill_filespec(two, new_sha1, new_mode);
+       dp = diff_queue(&diff_queued_diff, one, two);
+       dp->score = score * MAX_SCORE / 100;
+       dp->status = status;
 }
 
 void diff_change(unsigned old_mode, unsigned new_mode,
                 const unsigned char *old_sha1,
                 const unsigned char *new_sha1,
-                const char *base, const char *path) {
+                const char *base, const char *path) 
+{
        char concatpath[PATH_MAX];
-       struct diff_spec spec[2];
-
-       memcpy(spec[0].blob_sha1, old_sha1, 20);
-       spec[0].mode = old_mode;
-       memcpy(spec[1].blob_sha1, new_sha1, 20);
-       spec[1].mode = new_mode;
-       spec[0].sha1_valid = spec[0].file_valid = 1;
-       spec[1].sha1_valid = spec[1].file_valid = 1;
+       struct diff_filespec *one, *two;
 
-       if (path) {
-               strcpy(concatpath, base);
-               strcat(concatpath, path);
+       if (reverse_diff) {
+               unsigned tmp;
+               const unsigned char *tmp_c;
+               tmp = old_mode; old_mode = new_mode; new_mode = tmp;
+               tmp_c = old_sha1; old_sha1 = new_sha1; new_sha1 = tmp_c;
        }
-       run_external_diff(path ? concatpath : base, &spec[0], &spec[1]);
+       if (!path) path = "";
+       sprintf(concatpath, "%s%s", base, path);
+       one = alloc_filespec(concatpath);
+       two = alloc_filespec(concatpath);
+       fill_filespec(one, old_sha1, old_mode);
+       fill_filespec(two, new_sha1, new_mode);
+
+       diff_queue(&diff_queued_diff, one, two);
 }
 
 void diff_unmerge(const char *path)
 {
-       run_external_diff(path, NULL, NULL);
+       struct diff_filespec *one, *two;
+       one = alloc_filespec(path);
+       two = alloc_filespec(path);
+       diff_queue(&diff_queued_diff, one, two);
 }