Add updates module and fix issues

updates/get.go

@@ -0,0 +1,77 @@
+package updates
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+
+	"github.com/Safing/portbase/log"
+)
+
+var (
+	ErrNotFound = errors.New("the requested file could not be found")
+)
+
+// GetPlatformFile returns the latest platform specific file identified by the given identifier.
+func GetPlatformFile(identifier string) (*File, error) {
+	identifier = filepath.Join(fmt.Sprintf("%s_%s", runtime.GOOS, runtime.GOARCH), identifier)
+	// From https://golang.org/pkg/runtime/#GOARCH
+	// GOOS is the running program's operating system target: one of darwin, freebsd, linux, and so on.
+	// GOARCH is the running program's architecture target: one of 386, amd64, arm, s390x, and so on.
+	return loadOrFetchFile(identifier)
+}
+
+// GetFile returns the latest generic file identified by the given identifier.
+func GetFile(identifier string) (*File, error) {
+	identifier = filepath.Join("all", identifier)
+	return loadOrFetchFile(identifier)
+}
+
+func getLatestFilePath(identifier string) (versionedFilePath, version string, stable bool, ok bool) {
+	updatesLock.RLock()
+	version, ok = stableUpdates[identifier]
+	if !ok {
+		version, ok = latestUpdates[identifier]
+		if !ok {
+			log.Tracef("updates: file %s does not exist", identifier)
+			return "", "", false, false
+			// TODO: if in development mode, reload latest index to check for newly sideloaded updates
+			// err := reloadLatest()
+		}
+	}
+	updatesLock.RUnlock()
+
+	// TODO: Fix for stable release
+	return getVersionedPath(identifier, version), version, false, true
+}
+
+func loadOrFetchFile(identifier string) (*File, error) {
+	versionedFilePath, version, stable, ok := getLatestFilePath(identifier)
+	if !ok {
+		// TODO: if in development mode, search updates dir for sideloaded apps
+		return nil, ErrNotFound
+	}
+
+	// build final filepath
+	realFilePath := filepath.Join(updateStoragePath, versionedFilePath)
+	if _, err := os.Stat(realFilePath); err == nil {
+		// file exists
+		return newFile(realFilePath, version, stable), nil
+	}
+
+	// download file
+	log.Tracef("updates: starting download of %s", versionedFilePath)
+	var err error
+	for tries := 0; tries < 5; tries++ {
+		err := fetchFile(realFilePath, versionedFilePath, tries)
+		if err != nil {
+			log.Tracef("updates: failed to download %s: %s, retrying (%d)", versionedFilePath, err, tries+1)
+		} else {
+			return newFile(realFilePath, version, stable), nil
+		}
+	}
+	log.Warningf("updates: failed to download %s: %s", versionedFilePath, err)
+	return nil, err
+}