Bug 1812518 - Allow a custom View for first party downloads

This will allow clients easily implement their own UI.

Backport of https://github.com/mozilla-mobile/firefox-android/commit/e678610bc10df96b8543c26fb5eb7c1ba26e3e20

components/feature/downloads/src/main/java/mozilla/components/feature/downloads/DownloadDialogFragment.kt

@@ -10,7 +10,7 @@ import mozilla.components.browser.state.state.content.DownloadState
 import mozilla.components.feature.downloads.DownloadDialogFragment.Companion.BYTES_TO_MB_LIMIT
 import mozilla.components.feature.downloads.DownloadDialogFragment.Companion.KILOBYTE
 import mozilla.components.feature.downloads.DownloadDialogFragment.Companion.MEGABYTE
-import mozilla.components.support.utils.DownloadUtils
+import mozilla.components.feature.downloads.ext.realFilenameOrGuessed
 
 /**
  * This is a general representation of a dialog meant to be used in collaboration with [DownloadsFeature]
@@ -34,11 +34,7 @@ abstract class DownloadDialogFragment : AppCompatDialogFragment() {
      */
     fun setDownload(download: DownloadState) {
         val args = arguments ?: Bundle()
-        args.putString(
-            KEY_FILE_NAME,
-            download.fileName
-                ?: DownloadUtils.guessFileName(null, download.destinationDirectory, download.url, download.contentType)
-        )
+        args.putString(KEY_FILE_NAME, download.realFilenameOrGuessed)
         args.putString(KEY_URL, download.url)
         args.putLong(KEY_CONTENT_LENGTH, download.contentLength ?: 0)
         arguments = args

components/feature/downloads/src/main/java/mozilla/components/feature/downloads/DownloadsFeature.kt

@@ -25,6 +25,7 @@ import mozilla.components.browser.state.state.SessionState
 import mozilla.components.browser.state.state.content.DownloadState
 import mozilla.components.browser.state.store.BrowserStore
 import mozilla.components.feature.downloads.DownloadDialogFragment.Companion.FRAGMENT_TAG
+import mozilla.components.feature.downloads.ext.realFilenameOrGuessed
 import mozilla.components.feature.downloads.manager.DownloadManager
 import mozilla.components.feature.downloads.manager.noop
 import mozilla.components.feature.downloads.manager.onDownloadStopped
@@ -41,6 +42,31 @@ import mozilla.components.support.ktx.kotlin.isSameOriginAs
 import mozilla.components.support.ktx.kotlinx.coroutines.flow.ifChanged
 import mozilla.components.support.utils.Browsers
 
+/**
+ * The name of the file to be downloaded.
+ */
+@JvmInline
+value class Filename(val value: String)
+
+/**
+ * The size of the file to be downloaded expressed as the number of `bytes`.
+ * The value will be `0` if the size is unknown.
+ */
+@JvmInline
+value class ContentSize(val value: Long)
+
+/**
+ * Action for when the positive button of a download dialog was tapped.
+ */
+@JvmInline
+value class PositiveActionCallback(val value: () -> Unit)
+
+/**
+ * Action for when the negative button of a download dialog was tapped.
+ */
+@JvmInline
+value class NegativeActionCallback(val value: () -> Unit)
+
 /**
  * Feature implementation to provide download functionality for the selected
  * session. The feature will subscribe to the selected session and listen
@@ -60,6 +86,7 @@ import mozilla.components.support.utils.Browsers
  * @property promptsStyling styling properties for the dialog.
  * @property shouldForwardToThirdParties Indicates if downloads should be forward to third party apps,
  * if there are multiple apps a chooser dialog will shown.
+ * @property customDownloadDialog An optional delegate for showing a download dialog.
  */
 @Suppress("LongParameterList", "LargeClass")
 class DownloadsFeature(
@@ -73,7 +100,8 @@ class DownloadsFeature(
     private val tabId: String? = null,
     private val fragmentManager: FragmentManager? = null,
     private val promptsStyling: PromptsStyling? = null,
-    private val shouldForwardToThirdParties: () -> Boolean = { false }
+    private val shouldForwardToThirdParties: () -> Boolean = { false },
+    private val customDownloadDialog: ((Filename, ContentSize, PositiveActionCallback, NegativeActionCallback) -> Unit)? = null,
 ) : LifecycleAwareFeature, PermissionsFeature {
 
     var onDownloadStopped: onDownloadStopped
@@ -163,13 +191,30 @@ class DownloadsFeature(
             false
         } else {
             if (applicationContext.isPermissionGranted(downloadManager.permissions.asIterable())) {
-                if (fragmentManager != null && !download.skipConfirmation) {
+                when {
+                    customDownloadDialog != null && !download.skipConfirmation -> {
+                        customDownloadDialog.invoke(
+                            Filename(download.realFilenameOrGuessed),
+                            ContentSize(download.contentLength ?: 0),
+                            PositiveActionCallback {
+                                startDownload(download)
+                                useCases.consumeDownload.invoke(tab.id, download.id)
+                            },
+                            NegativeActionCallback {
+                                useCases.cancelDownloadRequest.invoke(tab.id, download.id)
+                            },
+                        )
+                        false
+                    }
+                    fragmentManager != null && !download.skipConfirmation -> {
                         showDownloadDialog(tab, download)
                         false
-                } else {
+                    }
+                    else -> {
                         useCases.consumeDownload(tab.id, download.id)
                         startDownload(download)
                     }
+                }
             } else {
                 onNeedToRequestPermissions(downloadManager.permissions)
                 false

components/feature/downloads/src/main/java/mozilla/components/feature/downloads/ext/DownloadState.kt

@@ -47,3 +47,6 @@ internal fun DownloadState.withResponse(headers: Headers, stream: InputStream?):
         contentLength = contentLength ?: headers[CONTENT_LENGTH]?.toLongOrNull()
     )
 }
+
+internal val DownloadState.realFilenameOrGuessed
+    get() = fileName ?: DownloadUtils.guessFileName(null, destinationDirectory, url, contentType)