kvdb: add postgres

kvdb/postgres/driver.go

@@ -0,0 +1,86 @@
+// +build kvdb_postgres
+
+package postgres
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/btcsuite/btcwallet/walletdb"
+)
+
+const (
+	dbType = "postgres"
+)
+
+// parseArgs parses the arguments from the walletdb Open/Create methods.
+func parseArgs(funcName string, args ...interface{}) (context.Context,
+	*Config, string, error) {
+
+	if len(args) != 3 {
+		return nil, nil, "", fmt.Errorf("invalid number of arguments "+
+			"to %s.%s -- expected: context.Context, "+
+			"postgres.Config, string", dbType, funcName,
+		)
+	}
+
+	ctx, ok := args[0].(context.Context)
+	if !ok {
+		return nil, nil, "", fmt.Errorf("argument 0 to %s.%s is "+
+			"invalid -- expected: context.Context",
+			dbType, funcName,
+		)
+	}
+
+	config, ok := args[1].(*Config)
+	if !ok {
+		return nil, nil, "", fmt.Errorf("argument 1 to %s.%s is "+
+			"invalid -- expected: postgres.Config",
+			dbType, funcName,
+		)
+	}
+
+	prefix, ok := args[2].(string)
+	if !ok {
+		return nil, nil, "", fmt.Errorf("argument 2 to %s.%s is "+
+			"invalid -- expected string", dbType,
+			funcName)
+	}
+
+	return ctx, config, prefix, nil
+}
+
+// createDBDriver is the callback provided during driver registration that
+// creates, initializes, and opens a database for use.
+func createDBDriver(args ...interface{}) (walletdb.DB, error) {
+	ctx, config, prefix, err := parseArgs("Create", args...)
+	if err != nil {
+		return nil, err
+	}
+
+	return newPostgresBackend(ctx, config, prefix)
+}
+
+// openDBDriver is the callback provided during driver registration that opens
+// an existing database for use.
+func openDBDriver(args ...interface{}) (walletdb.DB, error) {
+	ctx, config, prefix, err := parseArgs("Open", args...)
+	if err != nil {
+		return nil, err
+	}
+
+	return newPostgresBackend(ctx, config, prefix)
+}
+
+func init() {
+	// Register the driver.
+	driver := walletdb.Driver{
+		DbType: dbType,
+		Create: createDBDriver,
+		Open:   openDBDriver,
+	}
+	if err := walletdb.RegisterDriver(driver); err != nil {
+		panic(fmt.Sprintf("Failed to regiser database driver '%s': %v",
+			dbType, err))
+	}
+}