WIP: reduce allocations due to declTypes

sqlite3.go

@@ -79,6 +79,39 @@ _sqlite3_exec(sqlite3* db, const char* pcmd, long long* rowid, long long* change
   return rv;
 }
 
+typedef enum {
+  GO_SQLITE3_TYPE_NONE,
+  GO_SQLITE3_TYPE_DATETIME,
+  GO_SQLITE3_TYPE_BOOLEAN
+} go_sqlite3_decl_type;
+
+go_sqlite3_decl_type _sqlite3_column_decltype_internal(sqlite3_stmt* stmt, int idx) {
+  const char *typ = sqlite3_column_decltype(stmt, idx);
+  if (typ != NULL) {
+    switch (typ[0]) {
+    case 'B':
+    case 'b':
+      if (sqlite3_stricmp(typ, "boolean") == 0) {
+        return GO_SQLITE3_TYPE_BOOLEAN;
+      }
+      break;
+    case 'D':
+    case 'd':
+      if (sqlite3_stricmp(typ, "date") == 0 || sqlite3_stricmp(typ, "datetime") == 0) {
+        return GO_SQLITE3_TYPE_DATETIME;
+      }
+      break;
+    case 'T':
+    case 't':
+      if (sqlite3_stricmp(typ, "timestamp") == 0) {
+        return GO_SQLITE3_TYPE_DATETIME;
+      }
+      break;
+    }
+  }
+  return GO_SQLITE3_TYPE_NONE;
+}
+
 #ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
 extern int _sqlite3_step_blocking(sqlite3_stmt *stmt);
 extern int _sqlite3_step_row_blocking(sqlite3_stmt* stmt, long long* rowid, long long* changes);
@@ -134,7 +167,6 @@ void _sqlite3_result_blob(sqlite3_context* ctx, const void* b, int l) {
   sqlite3_result_blob(ctx, b, l, SQLITE_TRANSIENT);
 }
 
-
 int _sqlite3_create_function(
   sqlite3 *db,
   const char *zFunctionName,
@@ -381,13 +413,14 @@ type SQLiteResult struct {
 
 // SQLiteRows implements driver.Rows.
 type SQLiteRows struct {
-	s        *SQLiteStmt
-	nc       int
-	cols     []string
-	decltype []string
-	cls      bool
-	closed   bool
-	ctx      context.Context // no better alternative to pass context into Next() method
+	s         *SQLiteStmt
+	nc        int
+	cols      []string
+	decltype  []string
+	xdecltype []uint8
+	cls       bool
+	closed    bool
+	ctx       context.Context // no better alternative to pass context into Next() method
 }
 
 type functionInfo struct {
@@ -2134,6 +2167,31 @@ func (rc *SQLiteRows) Columns() []string {
 	return rc.cols
 }
 
+func normalizeDeclType(s string) string {
+	switch s {
+	case "BLOB", "blob":
+		return "blob"
+	case "BOOLEAN", "boolean":
+		return "boolean"
+	case "DATE", "DATETIME", "TIMESTAMP", "date", "datetime", "timestamp":
+		return "timestamp"
+	// case "TIMESTAMP", "timestamp":
+	// 	return "timestamp"
+	// case "DATETIME", "datetime":
+	// 	return "datetime"
+	case "INTEGER", "integer":
+		return "integer"
+	case "TEXT", "text":
+		return "text"
+	case "INT", "int":
+		return "int"
+	default:
+		return strings.ToLower(s)
+	}
+}
+
+// TODO: the only values that are used here are:
+// columnTimestamp, columnDatetime, columnDate, "boolean"
 func (rc *SQLiteRows) declTypes() []string {
 	if rc.s.s != nil && rc.decltype == nil {
 		rc.decltype = make([]string, rc.nc)
@@ -2144,6 +2202,16 @@ func (rc *SQLiteRows) declTypes() []string {
 	return rc.decltype
 }
 
+func (rc *SQLiteRows) xdeclTypes() []uint8 {
+	if rc.s.s != nil && rc.xdecltype == nil {
+		rc.xdecltype = make([]uint8, rc.nc)
+		for i := 0; i < rc.nc; i++ {
+			rc.xdecltype[i] = uint8(C._sqlite3_column_decltype_internal(rc.s.s, C.int(i)))
+		}
+	}
+	return rc.xdecltype
+}
+
 // DeclTypes return column types.
 func (rc *SQLiteRows) DeclTypes() []string {
 	rc.s.mu.Lock()
@@ -2196,14 +2264,15 @@ func (rc *SQLiteRows) nextSyncLocked(dest []driver.Value) error {
 		return nil
 	}
 
-	rc.declTypes()
+	// rc.declTypes()
+	rc.xdeclTypes()
 
 	for i := range dest {
 		switch C.sqlite3_column_type(rc.s.s, C.int(i)) {
 		case C.SQLITE_INTEGER:
 			val := int64(C.sqlite3_column_int64(rc.s.s, C.int(i)))
-			switch rc.decltype[i] {
-			case columnTimestamp, columnDatetime, columnDate:
+			switch rc.xdecltype[i] {
+			case C.GO_SQLITE3_TYPE_DATETIME:
 				var t time.Time
 				// Assume a millisecond unix timestamp if it's 13 digits -- too
 				// large to be a reasonable timestamp in seconds.
@@ -2218,7 +2287,7 @@ func (rc *SQLiteRows) nextSyncLocked(dest []driver.Value) error {
 					t = t.In(rc.s.c.loc)
 				}
 				dest[i] = t
-			case "boolean":
+			case C.GO_SQLITE3_TYPE_BOOLEAN:
 				dest[i] = val > 0
 			default:
 				dest[i] = val
@@ -2242,8 +2311,8 @@ func (rc *SQLiteRows) nextSyncLocked(dest []driver.Value) error {
 			n := int(C.sqlite3_column_bytes(rc.s.s, C.int(i)))
 			s := C.GoStringN((*C.char)(unsafe.Pointer(C.sqlite3_column_text(rc.s.s, C.int(i)))), C.int(n))
 
-			switch rc.decltype[i] {
-			case columnTimestamp, columnDatetime, columnDate:
+			switch rc.xdecltype[i] {
+			case C.GO_SQLITE3_TYPE_DATETIME:
 				var t time.Time
 				s = strings.TrimSuffix(s, "Z")
 				for _, format := range SQLiteTimestampFormats {