Make no-cgo build work without source changes

go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/pkg/errors v0.9.1
 	github.com/shurcooL/sanitized_anchor_name v1.0.0 // indirect
 	github.com/skip2/go-qrcode v0.0.0-20191027152451-9434209cb086
+	golang.org/x/image v0.0.0-20200430140353-33d19683fad8
 	gopkg.in/yaml.v2 v2.2.8
 	maunium.net/go/mauflag v1.0.0
 	maunium.net/go/maulogger/v2 v2.1.1

go.sum

@@ -59,6 +59,8 @@ github.com/tulir/go-whatsapp v0.2.6 h1:d58cqz/iqcCDeT+uFjLso8oSgMTYqoxGhGhGOyyHB
 github.com/tulir/go-whatsapp v0.2.6/go.mod h1:gyw9zGup1/Y3ZQUueZaqz3iR/WX9a2Lth4aqEbXjkok=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2 h1:VklqNMn3ovrHsnt90PveolxSbWFaJdECFbxSq0Mqo2M=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/image v0.0.0-20200430140353-33d19683fad8 h1:6WW6V3x1P/jokJBpRQYUJnMHRP6isStQwCozxnU7XQw=
+golang.org/x/image v0.0.0-20200430140353-33d19683fad8/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20200301022130-244492dfa37a h1:GuSPYbZzB5/dcLNCwLQLsg3obCJtX9IJhpXkvY7kzk0=
 golang.org/x/net v0.0.0-20200301022130-244492dfa37a/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=

no-cgo.go

@@ -18,9 +18,21 @@
 
 package main
 
+import (
+	"image"
+	"io"
+
+	"golang.org/x/image/webp"
+)
+
 func (bridge *Bridge) initCrypto() error {
 	if !bridge.Config.Bridge.Encryption.Allow {
 		bridge.Log.Warnln("Bridge built without end-to-bridge encryption, but encryption is enabled in config")
 	}
 	bridge.Log.Debugln("Bridge built without end-to-bridge encryption")
+	return nil
+}
+
+func decodeWebp(r io.Reader) (image.Image, error) {
+	return webp.Decode(r)
 }

portal.go

@@ -34,7 +34,6 @@ import (
 	"sync"
 	"time"
 
-	"github.com/chai2010/webp"
 	"github.com/pkg/errors"
 	log "maunium.net/go/maulogger/v2"
 
@@ -989,7 +988,7 @@ func (portal *Portal) HandleMediaMessage(source *User, download func() ([]byte,
 
 	// synapse doesn't handle webp well, so we convert it. This can be dropped once https://github.com/matrix-org/synapse/issues/4382 is fixed
 	if mimeType == "image/webp" {
-		img, err := webp.Decode(bytes.NewReader(data))
+		img, err := decodeWebp(bytes.NewReader(data))
 		if err != nil {
 			portal.log.Errorfln("Failed to decode media for %s: %v", err)
 			return
@@ -1188,7 +1187,7 @@ func (portal *Portal) sendMatrixConnectionError(sender *User, eventID id.EventID
 		if sender.IsLoginInProgress() {
 			reconnect = "You have a login attempt in progress, please wait."
 		}
-		msg := format.RenderMarkdown("\u26a0 You are not connected to WhatsApp, so your message was not bridged. " + reconnect, true, false)
+		msg := format.RenderMarkdown("\u26a0 You are not connected to WhatsApp, so your message was not bridged. "+reconnect, true, false)
 		msg.MsgType = event.MsgNotice
 		_, err := portal.sendMainIntentMessage(msg)
 		if err != nil {
@@ -1229,7 +1228,6 @@ func (portal *Portal) HandleMatrixMessage(sender *User, evt *event.Event) {
 	}
 	portal.log.Debugfln("Received event %s", evt.ID)
 
-
 	ts := uint64(evt.Timestamp / 1000)
 	status := waProto.WebMessageInfo_ERROR
 	fromMe := true

webp.go

@@ -0,0 +1,14 @@
+// +build cgo
+
+package main
+
+import (
+	"image"
+	"io"
+
+	"github.com/chai2010/webp"
+)
+
+func decodeWebp(r io.Reader) (image.Image, error) {
+	return webp.Decode(r)
+}