magic pathspec: futureproof shorthand form

[git.git] / setup.c

diff --git a/setup.c b/setup.c
index 03cd84f2fcbf9cdbc25116308a9c2c9407af8e71..5048252d78638c2c6adcf8807442728ef4f37a5e 100644 (file)
--- a/setup.c
+++ b/setup.c
@@ -126,6 +126,108 @@ void verify_non_filename(const char *prefix, const char *arg)
            "Use '--' to separate filenames from revisions", arg);
 }
 
+/*
+ * Magic pathspec
+ *
+ * NEEDSWORK: These need to be moved to dir.h or even to a new
+ * pathspec.h when we restructure get_pathspec() users to use the
+ * "struct pathspec" interface.
+ *
+ * Possible future magic semantics include stuff like:
+ *
+ *     { PATHSPEC_NOGLOB, '!', "noglob" },
+ *     { PATHSPEC_ICASE, '\0', "icase" },
+ *     { PATHSPEC_RECURSIVE, '*', "recursive" },
+ *     { PATHSPEC_REGEXP, '\0', "regexp" },
+ *
+ */
+#define PATHSPEC_FROMTOP    (1<<0)
+
+struct pathspec_magic {
+       unsigned bit;
+       char mnemonic; /* this cannot be ':'! */
+       const char *name;
+} pathspec_magic[] = {
+       { PATHSPEC_FROMTOP, '/', "top" },
+};
+
+/*
+ * Take an element of a pathspec and check for magic signatures.
+ * Append the result to the prefix.
+ *
+ * For now, we only parse the syntax and throw out anything other than
+ * "top" magic.
+ *
+ * NEEDSWORK: This needs to be rewritten when we start migrating
+ * get_pathspec() users to use the "struct pathspec" interface.  For
+ * example, a pathspec element may be marked as case-insensitive, but
+ * the prefix part must always match literally, and a single stupid
+ * string cannot express such a case.
+ */
+const char *prefix_pathspec(const char *prefix, int prefixlen, const char *elt)
+{
+       unsigned magic = 0;
+       const char *copyfrom = elt;
+       int i;
+
+       if (elt[0] != ':') {
+               ; /* nothing to do */
+       } else if (elt[1] == '(') {
+               /* longhand */
+               const char *nextat;
+               for (copyfrom = elt + 2;
+                    *copyfrom && *copyfrom != ')';
+                    copyfrom = nextat) {
+                       size_t len = strcspn(copyfrom, ",)");
+                       if (copyfrom[len] == ')')
+                               nextat = copyfrom + len;
+                       else
+                               nextat = copyfrom + len + 1;
+                       if (!len)
+                               continue;
+                       for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
+                               if (strlen(pathspec_magic[i].name) == len &&
+                                   !strncmp(pathspec_magic[i].name, copyfrom, len)) {
+                                       magic |= pathspec_magic[i].bit;
+                                       break;
+                               }
+                       if (ARRAY_SIZE(pathspec_magic) <= i)
+                               die("Invalid pathspec magic '%.*s' in '%s'",
+                                   (int) len, copyfrom, elt);
+               }
+               if (*copyfrom == ')')
+                       copyfrom++;
+       } else if (!elt[1]) {
+               /* Just ':' -- no element! */
+               return NULL;
+       } else {
+               /* shorthand */
+               for (copyfrom = elt + 1;
+                    *copyfrom && *copyfrom != ':';
+                    copyfrom++) {
+                       char ch = *copyfrom;
+
+                       if (!is_pathspec_magic(ch))
+                               break;
+                       for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++)
+                               if (pathspec_magic[i].mnemonic == ch) {
+                                       magic |= pathspec_magic[i].bit;
+                                       break;
+                               }
+                       if (ARRAY_SIZE(pathspec_magic) <= i)
+                               die("Unimplemented pathspec magic '%c' in '%s'",
+                                   ch, elt);
+               }
+               if (*copyfrom == ':')
+                       copyfrom++;
+       }
+
+       if (magic & PATHSPEC_FROMTOP)
+               return xstrdup(copyfrom);
+       else
+               return prefix_path(prefix, prefixlen, copyfrom);
+}
+
 const char **get_pathspec(const char *prefix, const char **pathspec)
 {
        const char *entry = *pathspec;
@@ -147,8 +249,7 @@ const char **get_pathspec(const char *prefix, const char **pathspec)
        dst = pathspec;
        prefixlen = prefix ? strlen(prefix) : 0;
        while (*src) {
-               const char *p = prefix_path(prefix, prefixlen, *src);
-               *(dst++) = p;
+               *(dst++) = prefix_pathspec(prefix, prefixlen, *src);
                src++;
        }
        *dst = NULL;