Replace zero-length array decls with [].
[gitweb.git] / diff.c
diff --git a/diff.c b/diff.c
index dcefe983afd8a0c32fd9ba6d1c8abc6cb9bf6736..137d0d0c0c3eaaaa1c3c874c6e5f719e00a0d396 100644 (file)
--- a/diff.c
+++ b/diff.c
+/*
+ * Copyright (C) 2005 Junio C Hamano
+ */
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.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 char *diff_cmd = "diff -L 'k/%s' -L 'l/%s' ";
-static char *diff_opts = "-p -u";
-static char *diff_arg_forward  = " - '%s'";
-static char *diff_arg_reverse  = " '%s' -";
+static int reverse_diff;
+static int use_size_cache;
 
-void prepare_diff_cmd(void)
+static const char *external_diff(void)
 {
+       static const char *external_diff_cmd = NULL;
+       static int done_preparing = 0;
+
+       if (done_preparing)
+               return external_diff_cmd;
+
        /*
         * Default values above are meant to match the
         * Linux kernel development style.  Examples of
         * alternative styles you can specify via environment
         * variables are:
         *
-        * GIT_DIFF_CMD="diff -L '%s' -L '%s'"
         * GIT_DIFF_OPTS="-c";
         */
-       diff_cmd = getenv("GIT_DIFF_CMD") ? : diff_cmd;
-       diff_opts = getenv("GIT_DIFF_OPTS") ? : diff_opts;
+       if (gitenv("GIT_EXTERNAL_DIFF"))
+               external_diff_cmd = gitenv("GIT_EXTERNAL_DIFF");
+
+       /* In case external diff fails... */
+       diff_opts = gitenv("GIT_DIFF_OPTS") ? : diff_opts;
+
+       done_preparing = 1;
+       return external_diff_cmd;
+}
+
+#define TEMPFILE_PATH_LEN              50
+
+static struct diff_tempfile {
+       const char *name; /* filename external diff should read from */
+       char hex[41];
+       char mode[10];
+       char tmp_path[TEMPFILE_PATH_LEN];
+} diff_temp[2];
+
+static int count_lines(const char *filename)
+{
+       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 *const diff_cmd = "diff -L%s%s -L%s%s";
+       const char *const 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[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.
+        */
+       cmd_size = (strlen(diff_cmd) + strlen(diff_opts) +
+                       strlen(diff_arg) - 9);
+       for (i = 0; i < 2; i++) {
+               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[i];
+               }
+               cmd_size += (strlen(path0[i]) + strlen(path1[i]) +
+                            strlen(input_name_sq[i]));
+       }
+
+       cmd = xmalloc(cmd_size);
+
+       next_at = 0;
+       next_at += snprintf(cmd+next_at, cmd_size-next_at,
+                           diff_cmd,
+                           path0[0], path1[0], path0[1], path1[1]);
+       next_at += snprintf(cmd+next_at, cmd_size-next_at,
+                           " %s ", diff_opts);
+       next_at += snprintf(cmd+next_at, cmd_size-next_at,
+                           diff_arg, input_name_sq[0], input_name_sq[1]);
+
+       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
+ * prepare_temp_file() does not have to inflate and extract.
+ */
+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 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;
+
+       len = strlen(name);
+       pos = cache_name_pos(name, len);
+       if (pos < 0)
+               return 0;
+       ce = active_cache[pos];
+       if ((lstat(name, &st) < 0) ||
+           !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);
+               close(fd);
+               if (s->data == MAP_FAILED)
+                       goto err_empty;
+               s->should_munmap = 1;
+       }
+       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(struct diff_filespec *s)
+{
+       if (s->should_free)
+               free(s->data);
+       else if (s->should_munmap)
+               munmap(s->data, s->size);
+       free(s);
+}
+
+static void prep_temp_blob(struct diff_tempfile *temp,
+                          void *blob,
+                          unsigned long size,
+                          unsigned char *sha1,
+                          int mode)
+{
+       int fd;
+
+       fd = git_mkstemp(temp->tmp_path, TEMPFILE_PATH_LEN, ".diff_XXXXXX");
+       if (fd < 0)
+               die("unable to create temp-file");
+       if (write(fd, blob, size) != size)
+               die("unable to write temp-file");
+       close(fd);
+       temp->name = temp->tmp_path;
+       strcpy(temp->hex, sha1_to_hex(sha1));
+       temp->hex[40] = 0;
+       sprintf(temp->mode, "%06o", mode);
 }
 
-/* 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.
+static void prepare_temp_file(const char *name,
+                             struct diff_tempfile *temp,
+                             struct diff_filespec *one)
+{
+       if (!DIFF_FILE_VALID(one)) {
+       not_a_valid_file:
+               /* A '-' entry produces this for file-2, and
+                * a '+' entry produces this for file-1.
+                */
+               temp->name = "/dev/null";
+               strcpy(temp->hex, ".");
+               strcpy(temp->mode, ".");
+               return;
+       }
+
+       if (!one->sha1_valid ||
+           work_tree_matches(name, one->sha1)) {
+               struct stat st;
+               if (lstat(name, &st) < 0) {
+                       if (errno == ENOENT)
+                               goto not_a_valid_file;
+                       die("stat(%s): %s", name, strerror(errno));
+               }
+               if (S_ISLNK(st.st_mode)) {
+                       int ret;
+                       char *buf, buf_[1024];
+                       buf = ((sizeof(buf_) < st.st_size) ?
+                              xmalloc(st.st_size) : buf_);
+                       ret = readlink(name, buf, st.st_size);
+                       if (ret < 0)
+                               die("readlink(%s)", name);
+                       prep_temp_blob(temp, buf, st.st_size,
+                                      (one->sha1_valid ?
+                                       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->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 {
+               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);
+       }
+}
+
+static void remove_tempfile(void)
+{
+       int i;
+
+       for (i = 0; i < 2; i++)
+               if (diff_temp[i].name == diff_temp[i].tmp_path) {
+                       unlink(diff_temp[i].name);
+                       diff_temp[i].name = NULL;
+               }
+}
+
+static void remove_tempfile_on_signal(int signo)
+{
+       remove_tempfile();
+}
+
+/* An external diff command takes:
+ *
+ * diff-cmd name infile1 infile1-sha1 infile1-mode \
+ *               infile2 infile2-sha1 infile2-mode [ rename-to ]
  *
- * 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;
-
-       if (! (buf = malloc(cnt)))
-           return buf;
-       bp = buf;
-       while ((c = *src++)) {
-               if (c != '\'')
-                       *bp++ = c;
+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;
+       int status;
+       static int atexit_asked = 0;
+
+       if (one && two) {
+               prepare_temp_file(name, &temp[0], one);
+               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)) {
+                       atexit_asked = 1;
+                       atexit(remove_tempfile);
+               }
+               signal(SIGINT, remove_tempfile_on_signal);
+       }
+
+       fflush(NULL);
+       pid = fork();
+       if (pid < 0)
+               die("unable to fork");
+       if (!pid) {
+               if (pgm) {
+                       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);
+               }
+               /*
+                * otherwise we use the built-in one.
+                */
+               if (one && two)
+                       builtin_diff(name, other ? : name, temp, xfrm_msg,
+                                    complete_rewrite);
+               else
+                       printf("* Unmerged path %s\n", name);
+               exit(0);
+       }
+       if (waitpid(pid, &status, 0) < 0 ||
+           !WIFEXITED(status) || WEXITSTATUS(status)) {
+               /* Earlier we did not check the exit status because
+                * diff exits non-zero if files are different, and
+                * we are not interested in knowing that.  It was a
+                * mistake which made it harder to quit a diff-*
+                * session that uses the git-apply-patch-script as
+                * the GIT_EXTERNAL_DIFF.  A custom GIT_EXTERNAL_DIFF
+                * should also exit non-zero only when it wants to
+                * abort the entire diff-* session.
+                */
+               remove_tempfile();
+               fprintf(stderr, "external diff died, stopping at %s.\n", name);
+               exit(1);
+       }
+       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 DIFF_STATUS_COPIED:
+               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 DIFF_STATUS_RENAMED:
+               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 DIFF_STATUS_MODIFIED:
+               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 {
-                       bp = strcpy(bp, "'\\''");
-                       bp += 4;
-               }
-       }
-       *bp = 0;
-       return buf;
-}
-
-void show_differences(const char *name, /* filename on the filesystem */
-                     const char *label, /* diff label to use */
-                     void *old_contents, /* contents in core */
-                     unsigned long long old_size, /* size in core */
-                     int reverse /* 0: diff core file
-                                    1: diff file core */)
-{
-       FILE *f;
-       char *name_sq = sq_expand(name);
-       const char *label_sq = (name != label) ? sq_expand(label) : name_sq;
-       char *diff_arg = reverse ? diff_arg_reverse : diff_arg_forward;
-       int cmd_size = strlen(name_sq) + strlen(label_sq) * 2 +
-               strlen(diff_cmd) + strlen(diff_opts) + strlen(diff_arg);
-       char *cmd = malloc(cmd_size);
-       int next_at;
-
-       fflush(stdout);
-       next_at = snprintf(cmd, cmd_size, diff_cmd, label_sq, label_sq);
-       next_at += snprintf(cmd+next_at, cmd_size-next_at, "%s", diff_opts);
-       next_at += snprintf(cmd+next_at, cmd_size-next_at, diff_arg, name_sq);
-       f = popen(cmd, "w");
-       if (old_size)
-               fwrite(old_contents, old_size, 1, f);
-       pclose(f);
-       if (label_sq != name_sq)
-               free((void*)label_sq); /* constness */
-       free(name_sq);
-       free(cmd);
-}
-
-void show_diff_empty(const unsigned char *sha1,
-                    const char *name,
-                    int reverse)
-{
-       char *old;
-       unsigned long int size;
-       unsigned char type[20];
-
-       old = read_sha1_file(sha1, type, &size);
-       if (! old) {
-               error("unable to read blob object for %s (%s)", name,
-                     sha1_to_hex(sha1));
+                       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(p->one);
+       diff_free_filespec(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 *const 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 DIFF_STATUS_COPIED:
+       case DIFF_STATUS_RENAMED:
+               two_paths = 1;
+               break;
+       case DIFF_STATUS_ADDED:
+       case DIFF_STATUS_DELETED:
+               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 = DIFF_STATUS_UNMERGED;
+               else if (!DIFF_FILE_VALID(p->one))
+                       p->status = DIFF_STATUS_ADDED;
+               else if (!DIFF_FILE_VALID(p->two))
+                       p->status = DIFF_STATUS_DELETED;
+               else if (DIFF_PAIR_TYPE_CHANGED(p))
+                       p->status = DIFF_STATUS_TYPE_CHANGED;
+
+               /* 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 = DIFF_STATUS_COPIED;
+                               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 = DIFF_STATUS_COPIED;
+                               break;
+                       }
+                       if (!p->status)
+                               p->status = DIFF_STATUS_RENAMED;
+               }
+               else if (memcmp(p->one->sha1, p->two->sha1, 20) ||
+                        p->one->mode != p->two->mode)
+                       p->status = DIFF_STATUS_MODIFIED;
+               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 = DIFF_STATUS_UNKNOWN;
+               }
+       }
+       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 == DIFF_STATUS_UNKNOWN))
+                       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;
+               }
+               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, DIFF_STATUS_FILTER_AON)) {
+               int found;
+               for (i = found = 0; !found && i < q->nr; i++) {
+                       struct diff_filepair *p = q->queue[i];
+                       if (((p->status == DIFF_STATUS_MODIFIED) &&
+                            ((p->score &&
+                              strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
+                             (!p->score &&
+                              strchr(filter, DIFF_STATUS_MODIFIED)))) ||
+                           ((p->status != DIFF_STATUS_MODIFIED) &&
+                            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]);
        }
-       show_differences("/dev/null", name, old, size, reverse);
+       else {
+               /* Only the matching ones */
+               for (i = 0; i < q->nr; i++) {
+                       struct diff_filepair *p = q->queue[i];
+
+                       if (((p->status == DIFF_STATUS_MODIFIED) &&
+                            ((p->score &&
+                              strchr(filter, DIFF_STATUS_FILTER_BROKEN)) ||
+                             (!p->score &&
+                              strchr(filter, DIFF_STATUS_MODIFIED)))) ||
+                           ((p->status != DIFF_STATUS_MODIFIED) &&
+                            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_filespec *one, *two;
+
+       /* 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 (!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) 
+{
+       char concatpath[PATH_MAX];
+       struct diff_filespec *one, *two;
+
+       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;
+       }
+       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)
+{
+       struct diff_filespec *one, *two;
+       one = alloc_filespec(path);
+       two = alloc_filespec(path);
+       diff_queue(&diff_queued_diff, one, two);
 }