db: Implement the sqlite3 driver

This is the DB-specific counterpart to the previous commit.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

wallet/db_sqlite3.c

@@ -1,11 +1,147 @@
 #include <wallet/db_common.h>
 #include "gen_db_sqlite3.c"
+#include <ccan/ccan/tal/str/str.h>
+#include <lightningd/log.h>
+#include <sqlite3.h>
+#include <stdio.h>
+
 #if HAVE_SQLITE3
 
+static const char *db_sqlite3_expand(struct db_stmt *stmt)
+{
+#if HAVE_SQLITE3_EXPANDED_SQL
+	sqlite3_stmt *s = (sqlite3_stmt*)stmt->inner_stmt;
+	const char *sql;
+	char *expanded_sql;
+	expanded_sql = sqlite3_expanded_sql(s);
+	sql = tal_strdup(stmt, expanded_sql);
+	sqlite3_free(expanded_sql);
+	return sql;
+#else
+	return NULL;
+#endif
+}
+
+static const char *db_sqlite3_fmt_error(struct db_stmt *stmt)
+{
+	return tal_fmt(stmt, "%s: %s: %s", stmt->location, stmt->query->query,
+		       sqlite3_errmsg(stmt->db->conn));
+}
+
+static bool db_sqlite3_query(struct db_stmt *stmt)
+{
+	sqlite3_stmt *s;
+	sqlite3 *conn = (sqlite3*)stmt->db->conn;
+	int err;
+
+	err = sqlite3_prepare_v2(conn, stmt->query->query, -1, &s, NULL);
+
+	for (size_t i=0; i<stmt->query->placeholders; i++) {
+		struct db_binding *b = &stmt->bindings[i];
+
+		/* sqlite3 uses printf-like offsets, we don't... */
+		int pos = i+1;
+		switch (b->type) {
+		case DB_BINDING_UNINITIALIZED:
+			db_fatal("DB binding not initialized: position=%zu, "
+				 "query=\"%s\n",
+				 i, stmt->query->query);
+		case DB_BINDING_UINT64:
+			sqlite3_bind_int64(s, pos, b->v.u64);
+			break;
+		case DB_BINDING_INT:
+			sqlite3_bind_int(s, pos, b->v.i);
+			break;
+		case DB_BINDING_BLOB:
+			sqlite3_bind_blob(s, pos, b->v.blob, b->len,
+					  SQLITE_TRANSIENT);
+			break;
+		case DB_BINDING_TEXT:
+			sqlite3_bind_text(s, pos, b->v.text, b->len,
+					  SQLITE_TRANSIENT);
+			break;
+		case DB_BINDING_NULL:
+			sqlite3_bind_null(s, pos);
+			break;
+		}
+	}
+
+	if (err != SQLITE_OK) {
+		tal_free(stmt->error);
+		stmt->error = db_sqlite3_fmt_error(stmt);
+		return false;
+	}
+
+	stmt->inner_stmt = s;
+	return true;
+}
+
+static bool db_sqlite3_exec(struct db_stmt *stmt)
+{
+	int err;
+	if (!db_sqlite3_query(stmt)) {
+		/* If the prepare step caused an error we hand it up. */
+		return false;
+	}
+
+	err = sqlite3_step(stmt->inner_stmt);
+	if (err != SQLITE_DONE) {
+		tal_free(stmt->error);
+		stmt->error = db_sqlite3_fmt_error(stmt);
+		return false;
+	}
+
+	return true;
+}
+
+static bool db_sqlite3_step(struct db_stmt *stmt)
+{
+	sqlite3_stmt *s = (sqlite3_stmt*)stmt->inner_stmt;
+	return sqlite3_step(s) ==  SQLITE_ROW;
+}
+
+static bool db_sqlite3_begin_tx(struct db *db)
+{
+	int err;
+	char *errmsg;
+	err = sqlite3_exec(db->conn, "BEGIN TRANSACTION;", NULL, NULL, &errmsg);
+	if (err != SQLITE_OK) {
+		db->error = tal_fmt(db, "Failed to begin a transaction: %s", errmsg);
+		return false;
+	}
+	return true;
+}
+
+static bool db_sqlite3_commit_tx(struct db *db)
+{
+	int err;
+	char *errmsg;
+	err = sqlite3_exec(db->conn, "COMMIT;", NULL, NULL, &errmsg);
+	if (err != SQLITE_OK) {
+		db->error = tal_fmt(db, "Failed to begin a transaction: %s", errmsg);
+		return false;
+	}
+	return true;
+}
+
+static void db_sqlite3_stmt_free(struct db_stmt *stmt)
+{
+	if (stmt->inner_stmt)
+		sqlite3_finalize(stmt->inner_stmt);
+	tal_free(stmt);
+}
+
 struct db_config db_sqlite3_config = {
 	.name = "sqlite3",
 	.queries = db_sqlite3_queries,
 	.num_queries = DB_SQLITE3_QUERY_COUNT,
+	.expand_fn = &db_sqlite3_expand,
+	.exec_fn = &db_sqlite3_exec,
+	.query_fn = &db_sqlite3_query,
+	.step_fn = &db_sqlite3_step,
+	.begin_tx_fn = &db_sqlite3_begin_tx,
+	.commit_tx_fn = &db_sqlite3_commit_tx,
+	.stmt_free_fn = &db_sqlite3_stmt_free,
 };
 
 AUTODATA(db_backends, &db_sqlite3_config);