add a sqlite history backend (#2352)

irc/sqlite/config.go

@@ -0,0 +1,26 @@
+// Copyright (c) 2020 Shivaram Lingamneni
+// released under the MIT license
+
+package sqlite
+
+import (
+	"time"
+)
+
+const (
+	// maximum length in bytes of any message target (nickname or channel name) in its
+	// canonicalized (i.e., casefolded) state:
+	MaxTargetLength = 64
+)
+
+type Config struct {
+	// these are intended to be written directly into the config file:
+	Enabled      bool
+	DatabasePath string        `yaml:"database-path"`
+	BusyTimeout  time.Duration `yaml:"busy-timeout"`
+	MaxConns     int           `yaml:"max-conns"`
+
+	// XXX these are copied from elsewhere in the config:
+	ExpireTime           time.Duration
+	TrackAccountMessages bool
+}

irc/sqlite/stub.go

@@ -0,0 +1,34 @@
+//go:build !sqlite
+
+// Copyright (c) 2020 Shivaram Lingamneni
+// released under the MIT license
+
+// Package sqlite provides a stub implementation when SQLite support is not enabled.
+// To enable SQLite support, build with: make build_full
+// This stub prevents the binary from including the large modernc.org/sqlite driver dependencies.
+package sqlite
+
+import (
+	"errors"
+
+	"github.com/ergochat/ergo/irc/history"
+	"github.com/ergochat/ergo/irc/logger"
+)
+
+// Enabled is false when SQLite support is not compiled in
+const Enabled = false
+
+// SQLite is a stub implementation when the sqlite build tag is not present
+type SQLite struct {
+	history.Database
+}
+
+// NewSQLiteDatabase returns an error when SQLite support is not compiled in
+func NewSQLiteDatabase(logger *logger.Manager, config Config) (*SQLite, error) {
+	return nil, errors.New("SQLite support not enabled in this build. Rebuild with `make build_full` to enable")
+}
+
+// SetConfig is a no-op for the stub implementation
+func (s *SQLite) SetConfig(config Config) {
+	// no-op
+}