git-apply: pick up default filenames from "diff --git" header line

Pure mode changes, and deletes or creates of empty files won't have this
information anywhere else.

diff --git a/apply.c b/apply.c
index 36edd07..3606419 100644 (file)
--- a/apply.c
+++ b/apply.c
@@ -36,7 +36,6 @@ static int max_change, max_len;
  * things are flags, where -1 means "don't know yet".
  */
 static int linenr = 1;
-static char *def_name = NULL;
 
 struct fragment {
        unsigned long oldpos, oldlines;
@@ -47,7 +46,7 @@ struct fragment {
 };
 
 struct patch {
-       char *new_name, *old_name;
+       char *new_name, *old_name, *def_name;
        unsigned int old_mode, new_mode;
        int is_rename, is_copy, is_new, is_delete;
        int lines_added, lines_deleted;
@@ -193,15 +192,15 @@ static void parse_traditional_patch(const char *first, const char *second, struc
        if (is_dev_null(first)) {
                patch->is_new = 1;
                patch->is_delete = 0;
-               name = find_name(second, def_name, p_value, TERM_SPACE | TERM_TAB);
+               name = find_name(second, NULL, p_value, TERM_SPACE | TERM_TAB);
                patch->new_name = name;
        } else if (is_dev_null(second)) {
                patch->is_new = 0;
                patch->is_delete = 1;
-               name = find_name(first, def_name, p_value, TERM_EXIST | TERM_SPACE | TERM_TAB);
+               name = find_name(first, NULL, p_value, TERM_EXIST | TERM_SPACE | TERM_TAB);
                patch->old_name = name;
        } else {
-               name = find_name(first, def_name, p_value, TERM_EXIST | TERM_SPACE | TERM_TAB);
+               name = find_name(first, NULL, p_value, TERM_EXIST | TERM_SPACE | TERM_TAB);
                name = find_name(second, name, p_value, TERM_EXIST | TERM_SPACE | TERM_TAB);
                patch->old_name = patch->new_name = name;
        }
@@ -285,12 +284,14 @@ static int gitdiff_newmode(const char *line, struct patch *patch)
 static int gitdiff_delete(const char *line, struct patch *patch)
 {
        patch->is_delete = 1;
+       patch->old_name = patch->def_name;
        return gitdiff_oldmode(line, patch);
 }
 
 static int gitdiff_newfile(const char *line, struct patch *patch)
 {
        patch->is_new = 1;
+       patch->new_name = patch->def_name;
        return gitdiff_newmode(line, patch);
 }
 
@@ -336,6 +337,61 @@ static int gitdiff_unrecognized(const char *line, struct patch *patch)
        return -1;
 }
 
+static char *git_header_name(char *line)
+{
+       int len;
+       char *name, *second;
+
+       /*
+        * Find the first '/'
+        */
+       name = line;
+       for (;;) {
+               char c = *name++;
+               if (c == '\n')
+                       return NULL;
+               if (c == '/')
+                       break;
+       }
+
+       /*
+        * We don't accept absolute paths (/dev/null) as possibly valid
+        */
+       if (name == line+1)
+               return NULL;
+
+       /*
+        * Accept a name only if it shows up twice, exactly the same
+        * form.
+        */
+       for (len = 0 ; ; len++) {
+               char c = name[len];
+
+               switch (c) {
+               default:
+                       continue;
+               case '\n':
+                       break;
+               case '\t': case ' ':
+                       second = name+len;
+                       for (;;) {
+                               char c = *second++;
+                               if (c == '\n')
+                                       return NULL;
+                               if (c == '/')
+                                       break;
+                       }
+                       if (!memcmp(name, second, len)) {
+                               char *ret = xmalloc(len + 1);
+                               memcpy(ret, name, len);
+                               ret[len] = 0;
+                               return ret;
+                       }
+               }
+       }
+       return NULL;
+}
+
 /* Verify that we recognize the lines following a git header */
 static int parse_git_header(char *line, int len, unsigned int size, struct patch *patch)
 {
@@ -345,6 +401,14 @@ static int parse_git_header(char *line, int len, unsigned int size, struct patch
        patch->is_new = 0;
        patch->is_delete = 0;
 
+       /*
+        * Some things may not have the old name in the
+        * rest of the headers anywhere (pure mode changes,
+        * or removing or adding empty files), so we get
+        * the default name from the header.
+        */
+       patch->def_name = git_header_name(line + strlen("diff --git "));
+
        line += len;
        size -= len;
        linenr++;
@@ -494,7 +558,8 @@ static int find_header(char *line, unsigned long size, int *hdrsize, struct patc
                        int git_hdr_len = parse_git_header(line, len, size, patch);
                        if (git_hdr_len < 0)
                                continue;
-
+                       if (!patch->old_name && !patch->new_name)
+                               die("git diff header lacks filename information");
                        *hdrsize = git_hdr_len;
                        return offset;
                }
@@ -630,11 +695,8 @@ static void show_stats(struct patch *patch)
        char *name = patch->old_name;
        int len, max, add, del;
 
-       if (!name) {
+       if (!name)
                name = patch->new_name;
-               if (!name)
-                       return;
-       }
 
        /*
         * "scale" the filename