feat: improve webview version verification

This fixes the verification of Huawei WebViews, which use a different version code
 (com.huawei.webview)

In addition, this specifies a mechanism for a `PageFragment` to specify the minimum usable WebView
 version

feat: verify webview version and prevent loading blank screen
refactor: use WebViewVersion and WebViewVersionCode value classes and use finish() in PageFragement.kt
refactor: rename checkWebviewVersion to showDialogIfWebViewOutdated and use Context instead of Activity
feat: replace requiresModernWebView() with minimumWebViewVersion property
test: update WebViewUtilsTest to use accurate webview version data
Fix: Add Unit tests and implement selective blocking during importing for outdated webviews

Fixes 19914

Author: Fandroid745

AnkiDroid/src/main/java/com/ichi2/anki/DeckPicker.kt

@@ -186,14 +186,14 @@ import com.ichi2.utils.ImportUtils
 import com.ichi2.utils.NetworkUtils
 import com.ichi2.utils.Permissions
 import com.ichi2.utils.VersionUtils
-import com.ichi2.utils.checkWebviewVersion
 import com.ichi2.utils.configureView
 import com.ichi2.utils.customView
 import com.ichi2.utils.dp
 import com.ichi2.utils.message
 import com.ichi2.utils.negativeButton
 import com.ichi2.utils.positiveButton
 import com.ichi2.utils.show
+import com.ichi2.utils.showDialogIfWebViewOutdated
 import com.ichi2.utils.title
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
@@ -556,7 +556,7 @@ open class DeckPicker :
 
         shortAnimDuration = resources.getInteger(android.R.integer.config_shortAnimTime)
 
-        checkWebviewVersion(this)
+        with(this) { showDialogIfWebViewOutdated() }
 
         // If a review reminder deserialization error has recently occurred
         // (ex. on app boot, when the app opened, etc.), inform the user via a dialog

AnkiDroid/src/main/java/com/ichi2/anki/pages/AnkiPackageImporterFragment.kt

@@ -25,13 +25,17 @@ import com.ichi2.anki.CollectionManager
 import com.ichi2.anki.R
 import com.ichi2.anki.SingleFragmentActivity
 import com.ichi2.anki.hideShowButtonCss
+import com.ichi2.utils.OLDEST_WORKING_WEBVIEW_VERSION
+import com.ichi2.utils.WebViewVersion
 
 class AnkiPackageImporterFragment : PageFragment() {
     override val pagePath: String by lazy {
         val filePath = requireArguments().getString(KEY_FILE_PATH)
         "import-anki-package$filePath"
     }
 
+    override val minimumWebViewVersion: WebViewVersion = OLDEST_WORKING_WEBVIEW_VERSION
+
     override fun onCreateWebViewClient(savedInstanceState: Bundle?): PageWebViewClient {
         // the back callback is only enabled when import is running and showing progress
         val backCallback =

AnkiDroid/src/main/java/com/ichi2/anki/pages/CsvImporter.kt

@@ -27,6 +27,8 @@ import com.ichi2.anki.CollectionManager
 import com.ichi2.anki.R
 import com.ichi2.anki.SingleFragmentActivity
 import com.ichi2.anki.hideShowButtonCss
+import com.ichi2.utils.OLDEST_WORKING_WEBVIEW_VERSION
+import com.ichi2.utils.WebViewVersion
 
 /**
  * Anki page used to import text/csv files
@@ -37,6 +39,8 @@ class CsvImporter : PageFragment() {
         "import-csv$filePath"
     }
 
+    override val minimumWebViewVersion: WebViewVersion = OLDEST_WORKING_WEBVIEW_VERSION
+
     override fun onCreateWebViewClient(savedInstanceState: Bundle?): PageWebViewClient {
         // the back callback is only enabled when import is running and showing progress
         val backCallback =

AnkiDroid/src/main/java/com/ichi2/anki/pages/PageFragment.kt

@@ -30,6 +30,8 @@ import com.ichi2.anki.R
 import com.ichi2.anki.workarounds.OnWebViewRecreatedListener
 import com.ichi2.anki.workarounds.SafeWebViewLayout
 import com.ichi2.themes.Themes
+import com.ichi2.utils.WebViewVersion
+import com.ichi2.utils.showDialogIfWebViewOutdated
 import timber.log.Timber
 
 /**
@@ -64,6 +66,8 @@ abstract class PageFragment(
 
     protected open fun onWebViewCreated() { }
 
+    protected open val minimumWebViewVersion: WebViewVersion? = null
+
     /**
      * When the webview calls `BridgeCommand("foo")`, the PageFragment execute `bridgeCommands["foo"]`.
      * By default, only bridge command is allowed, subclasses must redefine it if they expect bridge commands.
@@ -103,10 +107,21 @@ abstract class PageFragment(
         server = AnkiServer(this).also { it.start() }
         webViewLayout = view.findViewById(R.id.webview_layout)
 
+        minimumWebViewVersion?.let { minVersion ->
+            val isOutdated =
+                with(requireContext()) {
+                    showDialogIfWebViewOutdated(minVersion) {
+                        requireActivity().finish()
+                    }
+                }
+            if (isOutdated) {
+                Timber.w("${this::class.simpleName} requires modern WebView (Chrome 90+), aborting load")
+                return
+            }
+        }
         view.findViewById<MaterialToolbar>(R.id.toolbar)?.setNavigationOnClickListener {
             requireActivity().onBackPressedDispatcher.onBackPressed()
         }
-
         setupWebView(savedInstanceState)
     }
 

AnkiDroid/src/main/java/com/ichi2/utils/WebViewUtils.kt

@@ -27,33 +27,52 @@ import androidx.annotation.VisibleForTesting
 import androidx.appcompat.app.AlertDialog
 import androidx.core.content.pm.PackageInfoCompat
 import androidx.webkit.WebViewCompat
-import com.ichi2.anki.AnkiActivity
 import com.ichi2.anki.R
 import com.ichi2.anki.common.crashreporting.CrashReportService
+import com.ichi2.anki.utils.openUrl
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 import timber.log.Timber
 
-internal const val OLDEST_WORKING_WEBVIEW_VERSION_CODE = 418306960L
-internal const val OLDEST_WORKING_WEBVIEW_VERSION = 85
+@JvmInline
+value class WebViewVersion(
+    val value: Int,
+)
+
+@JvmInline
+value class WebViewVersionCode(
+    val value: Long,
+)
+
+/** The Android package version code which corresponds to the Webview version. */
+internal val OLDEST_WORKING_WEBVIEW_VERSION_CODE = WebViewVersionCode(418306960L)
+
+/** The minimum supported Webview version(Human readable). */
+internal val OLDEST_WORKING_WEBVIEW_VERSION = WebViewVersion(85)
 
 /**
  * Shows a dialog if the current WebView version is older than the last supported version.
  */
-fun checkWebviewVersion(activity: AnkiActivity) {
-    val userVisibleCode = getChromeLikeWebViewVersionIfOutdated(activity) ?: return
+
+context(context: Context)
+fun showDialogIfWebViewOutdated(
+    minimumWebViewVersion: WebViewVersion = OLDEST_WORKING_WEBVIEW_VERSION,
+    onOutdated: () -> Unit = {},
+): Boolean {
+    val userVisibleCode = getChromeLikeWebViewVersionIfOutdated(context, minimumWebViewVersion) ?: return false
 
     // Provide guidance to the user if the WebView is outdated
-    val webviewPackageInfo = getAndroidSystemWebViewPackageInfo(activity.packageManager)
-    val legacyWebViewPackageInfo = getLegacyWebViewPackageInfo(activity.packageManager)
+    val webviewPackageInfo = WebViewCompat.getCurrentWebViewPackage(context)
+    val legacyWebViewPackageInfo = getLegacyWebViewPackageInfo(context.packageManager)
     // TODO modify the alert dialog text to handle the usage of developer builds for system WebView
     if (legacyWebViewPackageInfo != null) {
         Timber.w("WebView is outdated. %s: %s", legacyWebViewPackageInfo.packageName, legacyWebViewPackageInfo.versionName)
-        showOutdatedWebViewDialog(activity, userVisibleCode, R.string.link_legacy_webview_update)
+        showOutdatedWebViewDialog(context, userVisibleCode, R.string.link_legacy_webview_update, onOutdated)
     } else {
         Timber.w("WebView is outdated. %s: %s", webviewPackageInfo?.packageName, webviewPackageInfo?.versionName)
-        showOutdatedWebViewDialog(activity, userVisibleCode, R.string.link_webview_update)
+        showOutdatedWebViewDialog(context, userVisibleCode, R.string.link_webview_update, onOutdated)
     }
+    return true
 }
 
 @MainThread
@@ -77,16 +96,25 @@ fun getWebviewUserAgent(context: Context): String? {
  * Returns a Chrome-like WebView version if it is outdated, otherwise null if
  * cannot be determined at all or if okay
  */
-private fun getChromeLikeWebViewVersionIfOutdated(activity: AnkiActivity): Int? {
+private fun getChromeLikeWebViewVersionIfOutdated(
+    context: Context,
+    minimumWebViewVersion: WebViewVersion,
+): Int? {
     // If we cannot get the package information at all, return null
-    val webviewPackageInfo = getAndroidSystemWebViewPackageInfo(activity.packageManager) ?: return null
+    val webviewPackageInfo = WebViewCompat.getCurrentWebViewPackage(context) ?: return null
     val webviewVersion =
         webviewPackageInfo.versionName ?: run {
             Timber.w("Failed to obtain WebView version")
             return null
         }
     val versionCode = PackageInfoCompat.getLongVersionCode(webviewPackageInfo)
-    return checkWebViewVersionComponents(webviewPackageInfo.packageName, webviewVersion, versionCode, getWebviewUserAgent(activity))
+    return checkWebViewVersionComponents(
+        webviewPackageInfo.packageName,
+        webviewVersion,
+        versionCode,
+        getWebviewUserAgent(context),
+        minimumWebViewVersion,
+    )
 }
 
 @VisibleForTesting
@@ -95,34 +123,35 @@ fun checkWebViewVersionComponents(
     webviewVersion: String,
     versionCode: Long,
     userAgent: String?,
+    minimumWebViewVersion: WebViewVersion = OLDEST_WORKING_WEBVIEW_VERSION,
 ): Int? {
-    // Checking the version code works for most webview packages
-    if (versionCode >= OLDEST_WORKING_WEBVIEW_VERSION_CODE) {
-        Timber.d(
-            "WebView is up to date. %s: %s(%s)",
-            packageName,
-            webviewVersion,
-            versionCode.toString(),
-        )
-        return null
-    }
-
     // Sometimes the webview version code appears too old, and the package name does as well,
     // but it's a webview that advertises modern capabilities via User-Agent in "Chrome" section
     // Our warning is purely advisory, so, let's let those through if User-Agent looks okay
     userAgent?.let {
         val chromeRegex = """Chrome/(\d+)""".toRegex()
         val matchResult = chromeRegex.find(userAgent)?.groupValues?.get(1)
         matchResult?.toInt()?.let {
-            if (it < OLDEST_WORKING_WEBVIEW_VERSION) {
-                // If we got here, even the User-Agent says it's incompatible, return something
-                // potentially useful to the user as a browser version
+            if (it >= minimumWebViewVersion.value) {
+                // If the User-Agent says we are modern, trust it and skip further checks.
+                return null
+            } else {
+                // If the User-Agent is explicitly below the floor, return it immediately.
                 return it
             }
         }
     }
-
-    return null
+    // Checking the version code works for most webview packages
+    if (versionCode >= OLDEST_WORKING_WEBVIEW_VERSION_CODE.value) {
+        Timber.d(
+            "WebView is up to date. %s: %s(%s)",
+            packageName,
+            webviewVersion,
+            versionCode.toString(),
+        )
+        return null
+    }
+    return webviewVersion.split('.').firstOrNull()?.toIntOrNull()
 }
 
 data class WebViewInfo(
@@ -153,15 +182,17 @@ suspend fun getWebViewInfo(context: Context): WebViewInfo =
     }
 
 private fun showOutdatedWebViewDialog(
-    activity: AnkiActivity,
+    context: Context,
     installedVersion: Int,
     @StringRes learnMoreUrl: Int,
+    onDismiss: () -> Unit = {},
 ) {
-    AlertDialog.Builder(activity).show {
-        setMessage(activity.getString(R.string.webview_update_message, installedVersion, OLDEST_WORKING_WEBVIEW_VERSION))
+    AlertDialog.Builder(context).show {
+        setMessage(context.getString(R.string.webview_update_message, installedVersion, OLDEST_WORKING_WEBVIEW_VERSION.value))
         setPositiveButton(R.string.scoped_storage_learn_more) { _, _ ->
-            activity.openUrl(learnMoreUrl)
+            context.openUrl(learnMoreUrl)
         }
+        setOnDismissListener { onDismiss() }
     }
 }
 
@@ -172,26 +203,6 @@ private fun getLegacyWebViewPackageInfo(packageManager: PackageManager): Package
         null
     }
 
-/**
- * Returns a [PackageInfo] from the current system WebView, or `null` if unavailable
- */
-private fun getAndroidSystemWebViewPackageInfo(packageManager: PackageManager): PackageInfo? {
-    fun getPackage(packageName: String): PackageInfo? =
-        try {
-            packageManager.getPackageInfo(packageName, 0)
-        } catch (_: PackageManager.NameNotFoundException) {
-            null
-        }
-
-    // The WebView is called com.android.webview by default.
-    // Partner devices which ship with Google applications ship the Google-specific version
-    // of the WebView called com.google.android.webview.
-    // https://issues.chromium.org/issues/40419837#comment10
-
-    return getPackage("com.google.android.webview")
-        ?: getPackage("com.android.webview") // com.android.webview is used on API 24
-}
-
 /**
  * Enables debugging of web contents (HTML / CSS / JavaScript)
  * loaded into any WebViews of this application. This flag can be enabled

AnkiDroid/src/test/java/com/ichi2/utils/WebViewUtilsTest.kt

@@ -28,7 +28,7 @@ class WebViewUtilsTest {
             checkWebViewVersionComponents(
                 "com.google.android.webview",
                 "53.0.2785.124",
-                OLDEST_WORKING_WEBVIEW_VERSION_CODE - 1,
+                OLDEST_WORKING_WEBVIEW_VERSION_CODE.value - 1,
                 "Mozilla/5.0 (Linux; Android 7.0; Android SDK built for arm64 Build/NYC; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/53.0.2785.124 Mobile Safari/537.36",
             ),
             equalTo(53),
@@ -50,10 +50,20 @@ class WebViewUtilsTest {
             checkWebViewVersionComponents(
                 "com.google.android.webview",
                 "74.0.0.0",
-                OLDEST_WORKING_WEBVIEW_VERSION_CODE - 1,
+                OLDEST_WORKING_WEBVIEW_VERSION_CODE.value - 1,
                 "Mozilla/5.0 (Linux; Android 9; SM-A730F Build/PPR1.180610.011; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/130.0.6723.102 Mobile Safari/537.36",
             ),
             equalTo(null),
         )
+        assertThat(
+            "Known old huawei webview determined correctly",
+            checkWebViewVersionComponents(
+                "com.huawei.webview",
+                "unknown",
+                356L,
+                "Mozilla/5.0 (Linux; Android 10; CDY-AN90 Build/HUAWEICDY-AN90; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/78.0.3904.108 Mobile Safari/537.36",
+            ),
+            equalTo(78),
+        )
     }
 }