Move blocking work off the main thread and fix threading races (#4068)

* Defer startup work until first use

* Move cover work off the main thread

* Make tracker calls main-safe and token refresh thread-safe

Kitsu, Shikimori and MangaBaka refresh their token under a lock like
MAL, so parallel calls no longer refresh it twice.

* Fix extension threading and make installs cancellable

The store service read response bodies on Main, which failed with
NetworkOnMainThreadException for http stores.

* Move reader work off the main thread and save progress in order

* Serialize the downloader and fix download threading

* Stop blocking on WorkManager status queries

Also removes NotificationReceiver's open chapter action: nothing sends
it, and its handler used runBlocking.

* Start migration jobs on the migrator's dispatcher

They started undispatched, so each ran on the caller's thread until its
first suspension.

* Run screen and view model work on fitting dispatchers

* Launch work that outlives a screen on the app scope

A launch on another dispatcher is dropped if the screen closes before it
starts, which dialogs that dismiss right away often do. Only the UI
follow-up stays on viewModelScope.

* Remove the coroutine helper extensions

They hid which dispatcher and scope a call used, and the GlobalScope
ones hid that it was global.

core/common/src/main/kotlin/eu/kanade/tachiyomi/network/AndroidCookieJar.kt

@@ -7,7 +7,7 @@ import okhttp3.HttpUrl
 
 class AndroidCookieJar : CookieJar {
 
-    private val manager = CookieManager.getInstance()
+    private val manager by lazy { CookieManager.getInstance() }
 
     override fun saveFromResponse(url: HttpUrl, cookies: List<Cookie>) {
         val urlString = url.toString()

core/common/src/main/kotlin/eu/kanade/tachiyomi/network/JavaScriptEngine.kt

@@ -5,7 +5,8 @@ import app.cash.quickjs.QuickJs
 import dev.zacsweers.metro.AppScope
 import dev.zacsweers.metro.Inject
 import dev.zacsweers.metro.SingleIn
-import tachiyomi.core.common.util.lang.withIOContext
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
 
 /**
  * Util for evaluating JavaScript in sources.
@@ -23,7 +24,7 @@ class JavaScriptEngine(context: Context) {
      * @param script JavaScript to execute.
      * @return Result of JavaScript code as a primitive type.
      */
-    suspend fun <T> evaluate(script: String): T = withIOContext {
+    suspend fun <T> evaluate(script: String): T = withContext(Dispatchers.Default) {
         QuickJs.create().use {
             it.evaluate(script) as T
         }

core/common/src/main/kotlin/eu/kanade/tachiyomi/network/NetworkHelper.kt

@@ -26,7 +26,7 @@ class NetworkHelper(
 
     val cookieJar = AndroidCookieJar()
 
-    private val clientBuilder: OkHttpClient.Builder = run {
+    private fun clientBuilder(): OkHttpClient.Builder = run {
         val builder = OkHttpClient.Builder()
             .cookieJar(cookieJar)
             .connectTimeout(30.seconds)
@@ -65,18 +65,20 @@ class NetworkHelper(
         }
     }
 
-    val client = clientBuilder
-        .addInterceptor(
-            CloudflareInterceptor(context, cookieJar, scope, ::defaultUserAgentProvider),
-        )
-        .build()
+    val client: OkHttpClient by lazy {
+        clientBuilder()
+            .addInterceptor(
+                CloudflareInterceptor(context, cookieJar, scope, ::defaultUserAgentProvider),
+            )
+            .build()
+    }
 
     /**
      * @deprecated Since extension-lib 1.5
      */
     @Deprecated("The regular client handles Cloudflare by default")
     @Suppress("UNUSED")
-    val cloudflareClient: OkHttpClient = client
+    val cloudflareClient: OkHttpClient get() = client
 
     fun defaultUserAgentProvider() = preferences.defaultUserAgent.get().trim()
 }

core/common/src/main/kotlin/eu/kanade/tachiyomi/network/interceptor/WebViewInterceptor.kt

@@ -11,11 +11,12 @@ import eu.kanade.tachiyomi.util.system.setDefaultSettings
 import eu.kanade.tachiyomi.util.system.setUserAgent
 import eu.kanade.tachiyomi.util.system.toast
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
 import okhttp3.Headers
 import okhttp3.Interceptor
 import okhttp3.Request
 import okhttp3.Response
-import tachiyomi.core.common.util.lang.launchUI
 import tachiyomi.i18n.MR
 import java.util.Locale
 import java.util.concurrent.CountDownLatch
@@ -59,7 +60,7 @@ abstract class WebViewInterceptor(
         }
 
         if (!WebViewUtil.supportsWebView(context)) {
-            scope.launchUI {
+            scope.launch(Dispatchers.Main) {
                 context.toast(MR.strings.information_webview_required, Toast.LENGTH_LONG)
             }
             return response

core/common/src/main/kotlin/tachiyomi/core/common/util/lang/CoroutinesExtensions.kt

@@ -1,30 +0,0 @@
-package tachiyomi.core.common.util.lang
-
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.Job
-import kotlinx.coroutines.NonCancellable
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.withContext
-
-fun CoroutineScope.launchUI(block: suspend CoroutineScope.() -> Unit): Job =
-    launch(Dispatchers.Main, block = block)
-
-fun CoroutineScope.launchIO(block: suspend CoroutineScope.() -> Unit): Job =
-    launch(Dispatchers.IO, block = block)
-
-fun CoroutineScope.launchNonCancellable(block: suspend CoroutineScope.() -> Unit): Job =
-    launchIO { withContext(NonCancellable, block) }
-
-suspend fun <T> withUIContext(block: suspend CoroutineScope.() -> T) = withContext(
-    Dispatchers.Main,
-    block,
-)
-
-suspend fun <T> withIOContext(block: suspend CoroutineScope.() -> T) = withContext(
-    Dispatchers.IO,
-    block,
-)
-
-suspend fun <T> withNonCancellableContext(block: suspend CoroutineScope.() -> T) =
-    withContext(NonCancellable, block)