1 files changed, 210 insertions, 0 deletions
diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/permissions/Permissions.java b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/permissions/Permissions.java
new file mode 100644
index 000000000..c1b38f61c
--- /dev/null
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/permissions/Permissions.java
@@ -0,0 +1,210 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.permissions;
+
+import android.app.Activity;
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.support.annotation.NonNull;
+
+import org.mozilla.gecko.util.ThreadUtils;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+import java.util.concurrent.Callable;
+import java.util.concurrent.CancellationException;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.FutureTask;
+
+/**
+ * Convenience class for checking and prompting for runtime permissions.
+ *
+ * Example:
+ *
+ *    Permissions.from(activity)
+ *               .withPermissions(Manifest.permission.WRITE_EXTERNAL_STORAGE)
+ *               .onUiThread()
+ *               .andFallback(onPermissionDenied())
+ *               .run(onPermissionGranted())
+ *
+ * This example will run the runnable returned by onPermissionGranted() if the WRITE_EXTERNAL_STORAGE permission is
+ * already granted. Otherwise it will prompt the user and run the runnable returned by onPermissionGranted() or
+ * onPermissionDenied() depending on whether the user accepted or not. If onUiThread() is specified then all callbacks
+ * will be run on the UI thread.
+ */
+public class Permissions {
+    private static final Queue<PermissionBlock> waiting = new LinkedList<>();
+    private static final Queue<PermissionBlock> prompt = new LinkedList<>();
+
+    private static PermissionsHelper permissionHelper = new PermissionsHelper();
+
+    /**
+     * Entry point for checking (and optionally prompting for) runtime permissions.
+     *
+     * Note: The provided context needs to be an Activity context in order to prompt. Use doNotPrompt()
+     * for all other contexts.
+     */
+    public static PermissionBlock from(@NonNull Context context) {
+        return new PermissionBlock(context, permissionHelper);
+    }
+
+    /**
+     * This method will block until the specified permissions have been granted or denied by the user.
+     * If needed the user will be prompted.
+     *
+     * @return true if all of the permissions have been granted. False if any of the permissions have been denied.
+     */
+    public static boolean waitFor(@NonNull Activity activity, String... permissions) {
+        ThreadUtils.assertNotOnUiThread(); // We do not want to block the UI thread.
+
+        // This task will block until all of the permissions have been granted
+        final FutureTask<Boolean> blockingTask = new FutureTask<>(new Callable<Boolean>() {
+            @Override
+            public Boolean call() throws Exception {
+                return true;
+            }
+        });
+
+        // This runnable will cancel the task if any of the permissions have been denied
+        Runnable cancelBlockingTask = new Runnable() {
+            @Override
+            public void run() {
+                blockingTask.cancel(true);
+            }
+        };
+
+        Permissions.from(activity)
+                .withPermissions(permissions)
+                .andFallback(cancelBlockingTask)
+                .run(blockingTask);
+
+        try {
+            return blockingTask.get();
+        } catch (InterruptedException | ExecutionException | CancellationException e) {
+            return false;
+        }
+    }
+
+    /**
+     * Determine whether you have been granted particular permissions.
+     */
+    public static boolean has(Context context, String... permissions) {
+        return permissionHelper.hasPermissions(context, permissions);
+    }
+
+    /* package-private */ static void setPermissionHelper(PermissionsHelper permissionHelper) {
+        Permissions.permissionHelper = permissionHelper;
+    }
+
+    /**
+     * Callback for Activity.onRequestPermissionsResult(). All activities that prompt for permissions using this class
+     * should implement onRequestPermissionsResult() and call this method.
+     */
+    public static synchronized void onRequestPermissionsResult(@NonNull Activity activity, @NonNull String[] permissions, @NonNull int[] grantResults) {
+        processGrantResults(permissions, grantResults);
+
+        processQueue(activity, permissions, grantResults);
+    }
+
+    /* package-private */ static synchronized void prompt(Activity activity, PermissionBlock block) {
+        if (prompt.isEmpty()) {
+            prompt.add(block);
+            showPrompt(activity);
+        } else {
+            waiting.add(block);
+        }
+    }
+
+    private static synchronized void processGrantResults(@NonNull String[] permissions, @NonNull int[] grantResults) {
+        final HashSet<String> grantedPermissions = collectGrantedPermissions(permissions, grantResults);
+
+        while (!prompt.isEmpty()) {
+            final PermissionBlock block = prompt.poll();
+
+            if (allPermissionsGranted(block, grantedPermissions)) {
+                block.onPermissionsGranted();
+            } else {
+                block.onPermissionsDenied();
+            }
+        }
+    }
+
+    private static synchronized void processQueue(Activity activity, String[] permissions, int[] grantResults) {
+        final HashSet<String> deniedPermissions = collectDeniedPermissions(permissions, grantResults);
+
+        while (!waiting.isEmpty()) {
+            final PermissionBlock block = waiting.poll();
+
+            if (block.hasPermissions(activity)) {
+                block.onPermissionsGranted();
+            } else {
+                if (atLeastOnePermissionDenied(block, deniedPermissions)) {
+                    // We just prompted the user and one of the permissions of this block has been denied:
+                    // There's no reason to instantly prompt again; Just reject without prompting.
+                    block.onPermissionsDenied();
+                } else {
+                    prompt.add(block);
+                }
+            }
+        }
+
+        if (!prompt.isEmpty()) {
+            showPrompt(activity);
+        }
+    }
+
+    private static synchronized void showPrompt(Activity activity) {
+        HashSet<String> permissions = new HashSet<>();
+
+        for (PermissionBlock block : prompt) {
+            Collections.addAll(permissions, block.getPermissions());
+        }
+
+        permissionHelper.prompt(activity, permissions.toArray(new String[permissions.size()]));
+    }
+
+    private static HashSet<String> collectGrantedPermissions(@NonNull String[] permissions, @NonNull int[] grantResults) {
+        return filterPermissionsByResult(permissions, grantResults, PackageManager.PERMISSION_GRANTED);
+    }
+
+    private static HashSet<String> collectDeniedPermissions(@NonNull String[] permissions, @NonNull int[] grantResults) {
+        return filterPermissionsByResult(permissions, grantResults, PackageManager.PERMISSION_DENIED);
+    }
+
+    private static HashSet<String> filterPermissionsByResult(@NonNull String[] permissions, @NonNull int[] grantResults, int result) {
+        HashSet<String> grantedPermissions = new HashSet<>(permissions.length);
+        for (int i = 0; i < permissions.length; i++) {
+            if (grantResults[i] == result) {
+                grantedPermissions.add(permissions[i]);
+            }
+        }
+        return grantedPermissions;
+    }
+
+    private static boolean allPermissionsGranted(PermissionBlock block, HashSet<String> grantedPermissions) {
+        for (String permission : block.getPermissions()) {
+            if (!grantedPermissions.contains(permission)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    private static boolean atLeastOnePermissionDenied(PermissionBlock block, HashSet<String> deniedPermissions) {
+        for (String permission : block.getPermissions()) {
+            if (deniedPermissions.contains(permission)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+}