[RFC patch 1/2] lib: refactor _notmuch_message_has_term

[David Bremner]

With essentially the same code path, we can provide a key/value lookup
facility, for future use.
---
 lib/message.cc        | 68 ++++++++++++++++++++++++++++++++++++++++-----------
 lib/notmuch-private.h |  6 +++++
 2 files changed, 60 insertions(+), 14 deletions(-)

diff --git a/lib/message.cc b/lib/message.cc
index 6839305..90c2bb2 100644
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -1263,36 +1263,76 @@ _notmuch_message_remove_term (notmuch_message_t *message,
     return NOTMUCH_PRIVATE_STATUS_SUCCESS;
 }
 
+/*
+ * look for a term with given prefix. If value != NULL, return the
+ *  suffix of the first such term. If suffix == NULL, consider any
+ *  non-empty suffix a mismatch
+*/
+notmuch_private_status_t
+_notmuch_message_get_prefixed_term (notmuch_message_t *message,
+				    const char *prefix,
+				    const char **value)
+{
+    notmuch_private_status_t status = NOTMUCH_PRIVATE_STATUS_SUCCESS;
+
+    if (strlen (prefix) > NOTMUCH_TERM_MAX)
+	return NOTMUCH_PRIVATE_STATUS_TERM_TOO_LONG;
+
+    try {
+	/* Look for prefixed term */
+	Xapian::TermIterator i = message->doc.termlist_begin ();
+	i.skip_to (prefix);
+	if ((i == message->doc.termlist_end ()) ||
+	    (strncmp (prefix, (*i).c_str (), strlen(prefix)) != 0)) {
+	    status = NOTMUCH_PRIVATE_STATUS_NO_TERM_FOUND;
+	} else {
+	    std::string suffix = (*i).substr (strlen (prefix));
+	    if (value) {
+		*value =  talloc_strdup (message, suffix.c_str ());
+	    } else {
+		/* non-exact match considered failure */
+		if (suffix.length () > 0)
+		    status = NOTMUCH_PRIVATE_STATUS_NO_TERM_FOUND;
+	    }
+	}
+    } catch (Xapian::Error &error) {
+	status = NOTMUCH_PRIVATE_STATUS_XAPIAN_EXCEPTION;
+    }
+
+    return status;
+}
+
 notmuch_private_status_t
 _notmuch_message_has_term (notmuch_message_t *message,
 			   const char *prefix_name,
 			   const char *value,
 			   notmuch_bool_t *result)
 {
+    notmuch_bool_t out = TRUE;
+    notmuch_private_status_t status;
     char *term;
-    notmuch_bool_t out = FALSE;
-    notmuch_private_status_t status = NOTMUCH_PRIVATE_STATUS_SUCCESS;
 
     if (value == NULL)
 	return NOTMUCH_PRIVATE_STATUS_NULL_POINTER;
 
+
     term = talloc_asprintf (message, "%s%s",
 			    _find_prefix (prefix_name), value);
 
-    if (strlen (term) > NOTMUCH_TERM_MAX)
-	return NOTMUCH_PRIVATE_STATUS_TERM_TOO_LONG;
+    if (term == NULL) {
+	status = NOTMUCH_PRIVATE_STATUS_OUT_OF_MEMORY;
+	goto DONE;
+    }
 
-    try {
-	/* Look for the exact term */
-	Xapian::TermIterator i = message->doc.termlist_begin ();
-	i.skip_to (term);
-	if (i != message->doc.termlist_end () &&
-	    !strcmp ((*i).c_str (), term))
-	    out = TRUE;
-    } catch (Xapian::Error &error) {
-	status = NOTMUCH_PRIVATE_STATUS_XAPIAN_EXCEPTION;
+    status = _notmuch_message_get_prefixed_term (message, term, NULL);
+    if (status == NOTMUCH_PRIVATE_STATUS_NO_TERM_FOUND) {
+	status = NOTMUCH_PRIVATE_STATUS_SUCCESS;
+	out = FALSE;
     }
-    talloc_free (term);
+
+ DONE:
+    if (term)
+	talloc_free (term);
 
     *result = out;
     return status;
diff --git a/lib/notmuch-private.h b/lib/notmuch-private.h
index 9280797..f7eba4a 100644
--- a/lib/notmuch-private.h
+++ b/lib/notmuch-private.h
@@ -141,6 +141,7 @@ typedef enum _notmuch_private_status {
     /* Then add our own private values. */
     NOTMUCH_PRIVATE_STATUS_TERM_TOO_LONG = NOTMUCH_STATUS_LAST_STATUS,
     NOTMUCH_PRIVATE_STATUS_NO_DOCUMENT_FOUND,
+    NOTMUCH_PRIVATE_STATUS_NO_TERM_FOUND,
 
     NOTMUCH_PRIVATE_STATUS_LAST_STATUS
 } notmuch_private_status_t;
@@ -333,6 +334,11 @@ _notmuch_message_initialize_ghost (notmuch_message_t *message,
 void
 _notmuch_message_close (notmuch_message_t *message);
 
+notmuch_private_status_t
+_notmuch_message_get_prefixed_term (notmuch_message_t *message,
+				    const char *prefix,
+				    const char **suffix);
+
 /* Get a copy of the data in this message document.
  *
  * Caller should talloc_free the result when done.
-- 
2.8.1