fix(http): reset discarded prefetch progress on resume (#1462)

.github/workflows/test.yml

@@ -91,7 +91,7 @@ jobs:
           flutter-version: ${{ env.FLUTTER_VERSION }}
       - name: Test webview
         if: runner.os == 'Windows'
-        run: go test -tags webview -v -timeout 300s ./internal/webview/goprovider/
+        run: go test -tags webview -v -count=1 -timeout 300s ./internal/webview/goprovider/
         env:
           CGO_ENABLED: 1
       - name: Test webview
@@ -107,7 +107,7 @@ jobs:
 
           cd ui/flutter
           flutter pub get
-          flutter run -d macos >"$LOG_PATH" 2>&1 &
+          flutter run --machine -d macos >"$LOG_PATH" 2>&1 &
           FLUTTER_PID=$!
           cd ../..
 
@@ -116,7 +116,26 @@ jobs:
           }
           trap cleanup EXIT
 
-          if ! go test -tags webview -v -timeout 600s ./internal/webview/rpcprovider/ -args -webview-rpc-network unix -webview-rpc-address "$SOCKET_PATH"; then
+          FLUTTER_STARTED=false
+          for _ in $(seq 1 600); do
+            if grep -Eq '"event"[[:space:]]*:[[:space:]]*"app\.started"' "$LOG_PATH"; then
+              FLUTTER_STARTED=true
+              break
+            fi
+            if ! kill -0 "$FLUTTER_PID" >/dev/null 2>&1; then
+              echo "Flutter exited before reporting app.started"
+              cat "$LOG_PATH"
+              exit 1
+            fi
+            sleep 1
+          done
+          if [[ "$FLUTTER_STARTED" != true ]]; then
+            echo "Timed out waiting for Flutter to report app.started"
+            cat "$LOG_PATH"
+            exit 1
+          fi
+
+          if ! go test -tags webview -v -count=1 -timeout 600s ./internal/webview/rpcprovider/ -args -webview-rpc-network unix -webview-rpc-address "$SOCKET_PATH"; then
             cat "$LOG_PATH"
             exit 1
           fi

internal/protocol/http/fetcher.go

@@ -584,6 +584,10 @@ func (f *Fetcher) cleanupPrefetchFile() {
 		os.Remove(f.prefetchFilePath)
 		f.prefetchFilePath = ""
 	}
+	// The byte count is only reusable while the backing prefetch file exists.
+	// Pause may discard that file before the first Start, so retaining the
+	// count would make the next Start skip bytes that were never copied.
+	f.prefetchSize.Store(0)
 }
 
 func (f *Fetcher) Start() error {

internal/protocol/http/fetcher_test.go

@@ -1,7 +1,9 @@
 package http
 
 import (
+	"bytes"
 	"context"
+	"crypto/md5"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -377,6 +379,59 @@ func TestFetcher_DownloadContinue(t *testing.T) {
 	downloadContinue(listener, 16, t)
 }
 
+func TestFetcher_PauseBeforeStartDiscardsPrefetchProgress(t *testing.T) {
+	payload := make([]byte, 32*1024*1024)
+	for i := range payload {
+		payload[i] = byte(i % 251)
+	}
+	prefetchServed := make(chan struct{}, 1)
+	server := httptest.NewServer(gohttp.HandlerFunc(func(w gohttp.ResponseWriter, r *gohttp.Request) {
+		if r.Header.Get(base.HttpHeaderRange) == "" {
+			w.Header().Set(base.HttpHeaderAcceptRanges, base.HttpHeaderBytes)
+			w.Header().Set(base.HttpHeaderContentLength, fmt.Sprintf("%d", len(payload)))
+			w.WriteHeader(gohttp.StatusOK)
+			if _, err := w.Write(payload); err == nil {
+				prefetchServed <- struct{}{}
+			}
+			return
+		}
+		gohttp.ServeContent(w, r, test.BuildName, time.Unix(0, 0), bytes.NewReader(payload))
+	}))
+	defer server.Close()
+
+	fetcher := buildFetcher()
+	if err := fetcher.Resolve(&base.Request{URL: server.URL + "/" + test.BuildName}, &base.Options{
+		Path: t.TempDir(),
+		Name: test.DownloadName,
+		Extra: &http.OptsExtra{
+			Connections: 2,
+		},
+	}); err != nil {
+		t.Fatal(err)
+	}
+	select {
+	case <-prefetchServed:
+	case <-time.After(5 * time.Second):
+		t.Fatal("timed out waiting for resolve prefetch response")
+	}
+
+	if err := fetcher.Pause(); err != nil {
+		t.Fatal(err)
+	}
+	if err := fetcher.Start(); err != nil {
+		t.Fatal(err)
+	}
+	if err := fetcher.Wait(); err != nil {
+		t.Fatal(err)
+	}
+
+	want := fmt.Sprintf("%x", md5.Sum(payload))
+	got := test.FileMd5(fetcher.Meta().SingleFilepath())
+	if want != got {
+		t.Fatalf("download after pause before start got MD5 %s, want %s", got, want)
+	}
+}
+
 func TestFetcher_DownloadContinue_NoRangeRestart(t *testing.T) {
 	listener := test.StartTestNoRangeSlowServer(time.Millisecond)
 	defer listener.Close()

internal/webview/goprovider/provider.go

@@ -81,6 +81,10 @@ type nativeCookieJSON struct {
 
 var providerSeq atomic.Uint64
 
+// Keep native page creation aligned with the provider availability budget used
+// by the integration contract. Cold WebView2 startup can exceed ten seconds.
+const startupTimeout = time.Minute
+
 func newPageWrapper(opts enginewebview.OpenOptions) *pageWrapper {
 	seq := providerSeq.Add(1)
 	return &pageWrapper{
@@ -142,7 +146,7 @@ func (p *pageWrapper) start() error {
 	case err := <-p.ready:
 		p.tracef("open %dms", time.Since(startedAt).Milliseconds())
 		return err
-	case <-time.After(10 * time.Second):
+	case <-time.After(startupTimeout):
 		p.tracef("open timeout %dms", time.Since(startedAt).Milliseconds())
 		return fmt.Errorf("webview startup timeout")
 	}

internal/webview/integrationtest/contract.go

@@ -14,6 +14,10 @@ import (
 
 const TestUserAgent = "GopeedWebViewIntegration/1.0"
 
+// Providers may need to initialize an external host or a native browser runtime
+// before the first page can be created.
+const defaultAvailabilityTimeout = time.Minute
+
 type ContractOptions struct {
 	AvailabilityTimeout time.Duration
 	CookieDomainMode    CookieDomainMode
@@ -32,7 +36,7 @@ func RunProviderContract(t *testing.T, provider enginewebview.Provider, opts Con
 
 	timeout := opts.AvailabilityTimeout
 	if timeout <= 0 {
-		timeout = 10 * time.Second
+		timeout = defaultAvailabilityTimeout
 	}
 	waitForProviderAvailable(t, provider, timeout)
 

internal/webview/rpcprovider/provider_integration_test.go

@@ -7,7 +7,6 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
-	"time"
 
 	"github.com/GopeedLab/gopeed/internal/webview/integrationtest"
 	enginewebview "github.com/GopeedLab/gopeed/pkg/download/engine/webview"
@@ -26,9 +25,8 @@ func TestProviderContract(t *testing.T) {
 		Token:   *webViewRPCToken,
 	})
 	integrationtest.RunProviderContract(t, provider, integrationtest.ContractOptions{
-		AvailabilityTimeout: 5 * time.Minute,
-		CookieDomainMode:    integrationtest.CookieDomainModeRequired,
-		CookieTestURL:       "https://example.com/",
+		CookieDomainMode: integrationtest.CookieDomainModeRequired,
+		CookieTestURL:    "https://example.com/",
 	})
 }