real_path_internal(): add comment explaining use of cwd

diff --git a/builtin/apply.c b/builtin/apply.c
index d453c833782c6aae4dd04fb9f9f68c3a8211d3d5..156b3ce3b72f51013baacff0a8ffd37ac97e6158 100644 (file)
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -188,7 +188,6 @@ struct patch {
        int is_new, is_delete;  /* -1 = unknown, 0 = false, 1 = true */
        int rejected;
        unsigned ws_rule;
-       unsigned long deflate_origlen;
        int lines_added, lines_deleted;
        int score;
        unsigned int is_toplevel_relative:1;
@@ -1096,15 +1095,23 @@ static int gitdiff_unrecognized(const char *line, struct patch *patch)
        return -1;
 }
 
-static const char *stop_at_slash(const char *line, int llen)
+/*
+ * Skip p_value leading components from "line"; as we do not accept
+ * absolute paths, return NULL in that case.
+ */
+static const char *skip_tree_prefix(const char *line, int llen)
 {
-       int nslash = p_value;
+       int nslash;
        int i;
 
+       if (!p_value)
+               return (llen && line[0] == '/') ? NULL : line;
+
+       nslash = p_value;
        for (i = 0; i < llen; i++) {
                int ch = line[i];
                if (ch == '/' && --nslash <= 0)
-                       return &line[i];
+                       return (i == 0) ? NULL : &line[i + 1];
        }
        return NULL;
 }
@@ -1134,12 +1141,11 @@ static char *git_header_name(const char *line, int llen)
                if (unquote_c_style(&first, line, &second))
                        goto free_and_fail1;
 
-               /* advance to the first slash */
-               cp = stop_at_slash(first.buf, first.len);
-               /* we do not accept absolute paths */
-               if (!cp || cp == first.buf)
+               /* strip the a/b prefix including trailing slash */
+               cp = skip_tree_prefix(first.buf, first.len);
+               if (!cp)
                        goto free_and_fail1;
-               strbuf_remove(&first, 0, cp + 1 - first.buf);
+               strbuf_remove(&first, 0, cp - first.buf);
 
                /*
                 * second points at one past closing dq of name.
@@ -1153,22 +1159,21 @@ static char *git_header_name(const char *line, int llen)
                if (*second == '"') {
                        if (unquote_c_style(&sp, second, NULL))
                                goto free_and_fail1;
-                       cp = stop_at_slash(sp.buf, sp.len);
-                       if (!cp || cp == sp.buf)
+                       cp = skip_tree_prefix(sp.buf, sp.len);
+                       if (!cp)
                                goto free_and_fail1;
                        /* They must match, otherwise ignore */
-                       if (strcmp(cp + 1, first.buf))
+                       if (strcmp(cp, first.buf))
                                goto free_and_fail1;
                        strbuf_release(&sp);
                        return strbuf_detach(&first, NULL);
                }
 
                /* unquoted second */
-               cp = stop_at_slash(second, line + llen - second);
-               if (!cp || cp == second)
+               cp = skip_tree_prefix(second, line + llen - second);
+               if (!cp)
                        goto free_and_fail1;
-               cp++;
-               if (line + llen - cp != first.len + 1 ||
+               if (line + llen - cp != first.len ||
                    memcmp(first.buf, cp, first.len))
                        goto free_and_fail1;
                return strbuf_detach(&first, NULL);
@@ -1180,10 +1185,9 @@ static char *git_header_name(const char *line, int llen)
        }
 
        /* unquoted first name */
-       name = stop_at_slash(line, llen);
-       if (!name || name == line)
+       name = skip_tree_prefix(line, llen);
+       if (!name)
                return NULL;
-       name++;
 
        /*
         * since the first name is unquoted, a dq if exists must be
@@ -1197,10 +1201,9 @@ static char *git_header_name(const char *line, int llen)
                        if (unquote_c_style(&sp, second, NULL))
                                goto free_and_fail2;
 
-                       np = stop_at_slash(sp.buf, sp.len);
-                       if (!np || np == sp.buf)
+                       np = skip_tree_prefix(sp.buf, sp.len);
+                       if (!np)
                                goto free_and_fail2;
-                       np++;
 
                        len = sp.buf + sp.len - np;
                        if (len < second - name &&
@@ -1232,13 +1235,27 @@ static char *git_header_name(const char *line, int llen)
                case '\n':
                        return NULL;
                case '\t': case ' ':
-                       second = stop_at_slash(name + len, line_len - len);
+                       /*
+                        * Is this the separator between the preimage
+                        * and the postimage pathname?  Again, we are
+                        * only interested in the case where there is
+                        * no rename, as this is only to set def_name
+                        * and a rename patch has the names elsewhere
+                        * in an unambiguous form.
+                        */
+                       if (!name[len + 1])
+                               return NULL; /* no postimage name */
+                       second = skip_tree_prefix(name + len + 1,
+                                                 line_len - (len + 1));
                        if (!second)
                                return NULL;
-                       second++;
-                       if (second[len] == '\n' && !strncmp(name, second, len)) {
+                       /*
+                        * Does len bytes starting at "name" and "second"
+                        * (that are separated by one HT or SP we just
+                        * found) exactly match?
+                        */
+                       if (second[len] == '\n' && !strncmp(name, second, len))
                                return xmemdupz(name, len);
-                       }
                }
        }
 }
@@ -4297,7 +4314,7 @@ int cmd_apply(int argc, const char **argv, const char *prefix_)
                OPT_NOOP_NOARG(0, "allow-binary-replacement"),
                OPT_NOOP_NOARG(0, "binary"),
                OPT_BOOLEAN(0, "numstat", &numstat,
-                       N_("shows number of added and deleted lines in decimal notation")),
+                       N_("show number of added and deleted lines in decimal notation")),
                OPT_BOOLEAN(0, "summary", &summary,
                        N_("instead of applying the patch, output a summary for the input")),
                OPT_BOOLEAN(0, "check", &check,