[Patch v7 05/14] quote_and_decode_query: new function to quote hex-decoded queries

[david at tethera.net]

From: David Bremner <bremner at debian.org>

The query is split into tokens, with ' ' and ':' as delimiters.  Any
token containing some hex-escaped character is quoted according to
Xapian rules.  This maps id:foo%20%22bar to id:"foo ""bar".
This intentionally does not quote prefixes, so they still work as prefixes.
---
 tag-util.c |   50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/tag-util.c b/tag-util.c
index f89669a..e1181f8 100644
--- a/tag-util.c
+++ b/tag-util.c
@@ -56,6 +56,56 @@ illegal_tag (const char *tag, notmuch_bool_t remove)
     return NULL;
 }
 
+static tag_parse_status_t
+quote_and_decode_query (void *ctx, char *encoded, const char *line_for_error,
+			char **query_string)
+{
+    char *tok = encoded;
+    size_t tok_len = 0;
+    char *buf = NULL;
+    size_t buf_len = 0;
+    tag_parse_status_t ret = TAG_PARSE_SUCCESS;
+
+    *query_string = talloc_strdup (ctx, "");
+
+    while (*query_string &&
+	   (tok = strtok_len (tok + tok_len, ": ", &tok_len)) != NULL) {
+	char delim = tok[tok_len];
+
+	*(tok + tok_len++) = '\0';
+
+	if (strcspn (tok, "%") < tok_len - 1) {
+	    /* something to decode */
+	    if (hex_decode_inplace (tok) != HEX_SUCCESS) {
+		ret = line_error (TAG_PARSE_INVALID, line_for_error,
+				  "hex decoding of token '%s' failed", tok);
+		goto DONE;
+	    }
+
+	    if (double_quote_str (ctx, tok, &buf, &buf_len)) {
+		ret = line_error (TAG_PARSE_OUT_OF_MEMORY,
+				  line_for_error, "aborting");
+		goto DONE;
+	    }
+	    *query_string = talloc_asprintf_append_buffer (
+		*query_string, "%s%c", buf, delim);
+
+	} else {
+	    /* This is not just an optimization, but used to preserve
+	     * prefixes like id:, which cannot be quoted.
+	     */
+	    *query_string = talloc_asprintf_append_buffer (
+		*query_string, "%s%c", tok, delim);
+	}
+
+    }
+
+  DONE:
+    if (ret != TAG_PARSE_SUCCESS && *query_string)
+	talloc_free (*query_string);
+    return ret;
+}
+
 tag_parse_status_t
 parse_tag_line (void *ctx, char *line,
 		tag_op_flag_t flags,
-- 
1.7.10.4