move struct pathspec and related functions to pathspec.[ch]

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 150 insertions, 0 deletions

diff --git a/pathspec.c b/pathspec.c
index 284f3970a3..133f8be98c 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -99,3 +99,153 @@ void die_if_path_beyond_symlink(const char *path, const char *prefix)
 		die(_("'%s' is beyond a symbolic link"), path + len);
 	}
 }
+
+/*
+ * 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)
+
+static 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.
+ */
+static 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 + 1;
+			else
+				/* handle ')' and '\0' */
+				nextat = copyfrom + len;
+			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 != ')')
+			die("Missing ')' at the end of pathspec magic in '%s'", elt);
+		copyfrom++;
+	} 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);
+}
+
+/*
+ * N.B. get_pathspec() is deprecated in favor of the "struct pathspec"
+ * based interface - see pathspec_magic above.
+ *
+ * Arguments:
+ *  - prefix - a path relative to the root of the working tree
+ *  - pathspec - a list of paths underneath the prefix path
+ *
+ * Iterates over pathspec, prepending each path with prefix,
+ * and return the resulting list.
+ *
+ * If pathspec is empty, return a singleton list containing prefix.
+ *
+ * If pathspec and prefix are both empty, return an empty list.
+ *
+ * This is typically used by built-in commands such as add.c, in order
+ * to normalize argv arguments provided to the built-in into a list of
+ * paths to process, all relative to the root of the working tree.
+ */
+const char **get_pathspec(const char *prefix, const char **pathspec)
+{
+	const char *entry = *pathspec;
+	const char **src, **dst;
+	int prefixlen;
+
+	if (!prefix && !entry)
+		return NULL;
+
+	if (!entry) {
+		static const char *spec[2];
+		spec[0] = prefix;
+		spec[1] = NULL;
+		return spec;
+	}
+
+	/* Otherwise we have to re-write the entries.. */
+	src = pathspec;
+	dst = pathspec;
+	prefixlen = prefix ? strlen(prefix) : 0;
+	while (*src) {
+		*(dst++) = prefix_pathspec(prefix, prefixlen, *src);
+		src++;
+	}
+	*dst = NULL;
+	if (!*pathspec)
+		return NULL;
+	return pathspec;
+}