Progress on ftag query

Query works for a single tag. Multi-tag SQL query looks fine but does
not work.

1 files changed, 28 insertions, 11 deletions

diff --git a/src/main.c b/src/main.c
index 6bdc28e..2f85c44 100644
--- a/src/main.c
+++ b/src/main.c
@@ -393,6 +393,29 @@ static int print_all_callback(void *_print_header, int count, char **cols, char
 	return 0;
 }
 
+/* Build the "join" part of the SQL query for the "ftag query" command. */
+static void ftag_query_join(sqlite3 *db, char *sql, int max_len,
+			    char **tags, int tag_count)
+{
+	assert(tag_count >= 0);
+	if (tag_count == 0) {
+		strncat(sql, "\t(SELECT id,canonical_name,full_name FROM files)\n",
+			max_len - strlen(sql));
+		assert(strlen(sql) <= max_len);
+		return;
+	}
+	char *prefix = "\t(SELECT id,canonical_name,full_name FROM file_tags JOIN\n";
+	strncat(sql, prefix, max_len - strlen(sql));
+	assert(strlen(sql) <= max_len);
+	ftag_query_join(db, sql, max_len, tags, tag_count-1);
+	char suffix[128];
+	memset(suffix, 0, sizeof(suffix));
+	snprintf(suffix, sizeof(suffix)-1,
+		 "\t\tON id = file\n\t\tWHERE tag = %d)\n", tag_count-1);
+	strncat(sql, suffix, max_len - strlen(sql));
+	assert(strlen(sql) <= max_len);
+}
+
 static void ftag_query(int argc, char **argv)
 {
 	if (argc == 0) {
@@ -427,22 +450,16 @@ static void ftag_query(int argc, char **argv)
 		argv += 2;
 	}
 	char sql[4096];
-	char sql_join[2048];
 	sqlite3 *db;
 	int rc;
 	rc = sqlite3_open(DATABASE_PATH, &db);
 	sqlite3_check(rc, db);
-	for (int join_idx = 0; join_idx < tag_count; join_idx++) {
-		int tag_id = get_id_by_col(db, "tags", "name", tags[join_idx]);
-		memset(sql_join, 0, sizeof(sql_join));
-		snprintf(sql_join, sizeof(sql_join)-1,
-			 "\t(SELECT id,canonical_name,full_name\n"
-			 " FROM (files JOIN file_tags ON id = file)\n"
-			 " WHERE tag = %d)\n", tag_id);
-		strcat(sql, sql_join);
-	}
+	char sql_join[2048];
+	memset(sql_join, 0, sizeof(sql_join));
+	ftag_query_join(db, sql_join, sizeof(sql_join)-1, tags, tag_count);
 	memset(sql, 0, sizeof(sql));
-	snprintf(sql, sizeof(sql)-1, "SELECT id,canonical_name,full_name FROM (\n%s);\n", sql_join);
+	snprintf(sql, sizeof(sql)-1,
+		 "SELECT id,canonical_name,full_name FROM (\n%s);\n", sql_join);
 	printf("%s: debug: SQL query is:\n%s", __func__, sql);
 	int print_header = 1;
 	rc = sqlite3_exec(db, sql, print_all_callback, &print_header, NULL);