Bug 1685614 - Use GeckoResult in EventDispatcher. r=owlish,snorp

This patch adds `queryString`, `queryBoolean`, `queryVoid` and `queryBundle` to
`EventDispatcher` in place of `dispatch(type, message, callback)`.

These `query*` methods returns a `GeckoResult` which can be manipulated using
`GeckoResult.map`.

Differential Revision: https://phabricator.services.mozilla.com/D96951

mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/WebExtensionTest.kt

@@ -1072,7 +1072,7 @@ class WebExtensionTest : BaseSessionTest() {
                 : WebExtension.SessionTabDelegate {
             override fun onCloseTab(source: WebExtension?,
                                     session: GeckoSession): GeckoResult<AllowOrDeny> {
-                assertEquals(extension, source)
+                assertEquals(extension.id, source!!.id)
                 assertEquals(expectedSession, session)
                 result.complete(null)
                 return GeckoResult.ALLOW

mobile/android/geckoview/src/main/java/org/mozilla/gecko/EventDispatcher.java

@@ -15,6 +15,7 @@ import org.mozilla.gecko.util.EventCallback;
 import org.mozilla.gecko.util.GeckoBundle;
 import org.mozilla.gecko.util.ThreadUtils;
 import org.mozilla.geckoview.BuildConfig;
+import org.mozilla.geckoview.GeckoResult;
 
 import android.os.Handler;
 import androidx.annotation.AnyThread;
@@ -221,6 +222,129 @@ public final class EventDispatcher extends JNIObject {
         dispatch(type, message, /* callback */ null);
     }
 
+    private abstract class CallbackResult<T> extends GeckoResult<T>
+            implements EventCallback {
+        @Override
+        public void sendError(final Object response) {
+            completeExceptionally(new QueryException(response));
+        }
+    }
+
+    public class QueryException extends Exception {
+        public final Object data;
+
+        public QueryException(final Object data) {
+            this.data = data;
+        }
+    }
+
+    /**
+     * Query event to any registered Bundle listeners (non-Gecko thread listeners).
+     *
+     * The returned GeckoResult completes when the event handler returns.
+     *
+     * @param type Event type
+     */
+    public GeckoResult<Void> queryVoid(final String type) {
+        return queryVoid(type, null);
+    }
+
+    /**
+     * Query event to any registered Bundle listeners (non-Gecko thread listeners).
+     *
+     * The returned GeckoResult completes when the event handler returns.
+     *
+     * @param type Event type
+     * @param message GeckoBundle message
+     */
+    public GeckoResult<Void> queryVoid(final String type, final GeckoBundle message) {
+        return query(type, message);
+    }
+
+    /**
+     * Query event to any registered Bundle listeners (non-Gecko thread listeners).
+     *
+     * The returned GeckoResult completes with the given boolean value returned by the handler.
+     *
+     * @param type Event type
+     */
+    public GeckoResult<Boolean> queryBoolean(final String type) {
+        return queryBoolean(type, null);
+    }
+
+    /**
+     * Query event to any registered Bundle listeners (non-Gecko thread listeners).
+     *
+     * The returned GeckoResult completes with the given boolean value returned by the handler.
+     *
+     * @param type Event type
+     * @param message GeckoBundle message
+     */
+    public GeckoResult<Boolean> queryBoolean(final String type, final GeckoBundle message) {
+        return query(type, message);
+    }
+
+    /**
+     * Query event to any registered Bundle listeners (non-Gecko thread listeners).
+     *
+     * The returned GeckoResult completes with the given String value returned by the handler.
+     *
+     * @param type Event type
+     */
+    public GeckoResult<String> queryString(final String type) {
+        return queryString(type, null);
+    }
+
+    /**
+     * Query event to any registered Bundle listeners (non-Gecko thread listeners).
+     *
+     * The returned GeckoResult completes with the given String value returned by the handler.
+     *
+     * @param type Event type
+     * @param message GeckoBundle message
+     */
+    public GeckoResult<String> queryString(final String type, final GeckoBundle message) {
+        return query(type, message);
+    }
+
+    /**
+     * Query event to any registered Bundle listeners (non-Gecko thread listeners).
+     *
+     * The returned GeckoResult completes with the given {@link GeckoBundle} value
+     * returned by the handler.
+     *
+     * @param type Event type
+     */
+    public GeckoResult<GeckoBundle> queryBundle(final String type) {
+        return queryBundle(type, null);
+    }
+
+    /**
+     * Query event to any registered Bundle listeners (non-Gecko thread listeners).
+     *
+     * The returned GeckoResult completes with the given {@link GeckoBundle} value
+     * returned by the handler.
+     *
+     * @param type Event type
+     * @param message GeckoBundle message
+     */
+    public GeckoResult<GeckoBundle> queryBundle(final String type, final GeckoBundle message) {
+        return query(type, message);
+    }
+
+    private <T> GeckoResult<T> query(final String type, final GeckoBundle message) {
+        final CallbackResult<T> result = new CallbackResult<T>() {
+            @Override
+            @SuppressWarnings("unchecked") // Not a lot we can do about this :(
+            public void sendSuccess(final Object response) {
+                complete((T) response);
+            }
+        };
+
+        dispatch(type, message, result);
+        return result;
+    }
+
     /**
      * Flushes pending messages of given types.
      *
@@ -259,8 +383,8 @@ public final class EventDispatcher extends JNIObject {
      * @param callback Optional object for callbacks from events.
      */
     @AnyThread
-    public void dispatch(final String type, final GeckoBundle message,
-                         final EventCallback callback) {
+    private void dispatch(final String type, final GeckoBundle message,
+                          final EventCallback callback) {
         final boolean isGeckoReady;
         synchronized (this) {
             isGeckoReady = isReadyForDispatchingToGecko();

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/ContentBlockingController.java

@@ -132,16 +132,27 @@ public class ContentBlockingController {
      */
     @UiThread
     public @NonNull GeckoResult<Boolean> checkException(final @NonNull GeckoSession session) {
-        final CallbackResult<Boolean> result = new CallbackResult<Boolean>() {
-            @Override
-            public void sendSuccess(final Object value) {
-                complete((Boolean) value);
-            }
-        };
         final GeckoBundle msg = new GeckoBundle(1);
         msg.putString("sessionId", session.getId());
-        EventDispatcher.getInstance().dispatch("ContentBlocking:CheckException", msg, result);
-        return result;
+        return EventDispatcher.getInstance()
+                .queryBoolean("ContentBlocking:CheckException", msg);
+    }
+
+    private List<ContentBlockingException> exceptionListFromBundle(final GeckoBundle value) {
+        final String[] principals = value.getStringArray("principals");
+        final String[] uris = value.getStringArray("uris");
+
+        if (principals == null || uris == null) {
+            throw new RuntimeException("Received invalid content blocking exception list");
+        }
+
+        final ArrayList<ContentBlockingException> res = new ArrayList<>(principals.length);
+
+        for (int i = 0; i < principals.length; i++) {
+            res.add(new ContentBlockingException(principals[i], uris[i]));
+        }
+
+        return Collections.unmodifiableList(res);
     }
 
     /**
@@ -152,28 +163,9 @@ public class ContentBlockingController {
      */
     @UiThread
     public @NonNull GeckoResult<List<ContentBlockingException>> saveExceptionList() {
-        final CallbackResult<List<ContentBlockingException>> result = new CallbackResult<List<ContentBlockingException>>() {
-            @Override
-            public void sendSuccess(final Object value) {
-                final String[] principals = ((GeckoBundle) value).getStringArray("principals");
-                final String[] uris = ((GeckoBundle) value).getStringArray("uris");
-
-                if (principals == null || uris == null) {
-                    completeExceptionally(new RuntimeException("Received invalid content blocking exception list"));
-                    return;
-                }
-
-                final ArrayList<ContentBlockingException> res = new ArrayList<ContentBlockingException>(principals.length);
-
-                for (int i = 0; i < principals.length; i++) {
-                    res.add(new ContentBlockingException(principals[i], uris[i]));
-                }
-
-                complete(Collections.unmodifiableList(res));
-            }
-        };
-        EventDispatcher.getInstance().dispatch("ContentBlocking:SaveList", null, result);
-        return result;
+        return EventDispatcher.getInstance()
+                .queryBundle("ContentBlocking:SaveList")
+                .map(this::exceptionListFromBundle);
     }
 
     /**
@@ -401,6 +393,15 @@ public class ContentBlockingController {
         }
     }
 
+    private List<LogEntry> logFromBundle(final GeckoBundle value) {
+        final GeckoBundle[] bundles = value.getBundleArray("log");
+        final ArrayList<LogEntry> logArray = new ArrayList<>(bundles.length);
+        for (GeckoBundle b : bundles) {
+            logArray.add(new LogEntry(b));
+        }
+        return Collections.unmodifiableList(logArray);
+    }
+
     /**
      * Get a log of all content blocking information for the site currently loaded by the
      * supplied {@link GeckoSession}.
@@ -411,18 +412,8 @@ public class ContentBlockingController {
      */
     @UiThread
     public @NonNull GeckoResult<List<LogEntry>> getLog(final @NonNull GeckoSession session) {
-        final CallbackResult<List<LogEntry>> result = new CallbackResult<List<LogEntry>>() {
-            @Override
-            public void sendSuccess(final Object value) {
-                final GeckoBundle[] bundles = ((GeckoBundle) value).getBundleArray("log");
-                final ArrayList<LogEntry> logArray = new ArrayList<LogEntry>(bundles.length);
-                for (GeckoBundle b : bundles) {
-                    logArray.add(new LogEntry(b));
-                }
-                complete(Collections.unmodifiableList(logArray));
-            }
-        };
-        session.getEventDispatcher().dispatch("ContentBlocking:RequestLog", null, result);
-        return result;
+        return session.getEventDispatcher()
+                .queryBundle("ContentBlocking:RequestLog")
+                .map(this::logFromBundle);
     }
 }

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/GeckoSession.java

@@ -953,14 +953,7 @@ public class GeckoSession {
      */
     @AnyThread
     public @NonNull GeckoResult<String> getUserAgent() {
-        final CallbackResult<String> result = new CallbackResult<String>() {
-            @Override
-            public void sendSuccess(final Object value) {
-                complete((String) value);
-            }
-        };
-        mEventDispatcher.dispatch("GeckoView:GetUserAgent", null, result);
-        return result;
+        return mEventDispatcher.queryString("GeckoView:GetUserAgent");
     }
 
     /**

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/SessionFinder.java

@@ -85,14 +85,8 @@ public final class SessionFinder {
         bundle.putString("searchString", searchString);
         addFlagsToBundle(flags, bundle);
 
-        final CallbackResult<FinderResult> result = new CallbackResult<FinderResult>() {
-            @Override
-            public void sendSuccess(final Object response) {
-                complete(new FinderResult((GeckoBundle) response));
-            }
-        };
-        mDispatcher.dispatch("GeckoView:FindInPage", bundle, result);
-        return result;
+        return mDispatcher.queryBundle("GeckoView:FindInPage", bundle)
+                .map(response -> new FinderResult(response));
     }
 
     /**

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/StorageController.java

@@ -112,20 +112,11 @@ public final class StorageController {
     @AnyThread
     public @NonNull GeckoResult<Void> clearData(
             final @StorageControllerClearFlags long flags) {
-        final CallbackResult<Void> result = new CallbackResult<Void>() {
-            @Override
-            public void sendSuccess(final Object response) {
-                complete(null);
-            }
-        };
-
         final GeckoBundle bundle = new GeckoBundle(1);
         bundle.putLong("flags", flags);
 
-        EventDispatcher.getInstance().dispatch(
-            "GeckoView:ClearData", bundle, result);
-
-        return result;
+        return EventDispatcher.getInstance()
+                .queryVoid("GeckoView:ClearData", bundle);
     }
 
     /**
@@ -146,21 +137,12 @@ public final class StorageController {
     public @NonNull GeckoResult<Void> clearDataFromHost(
             final @NonNull String host,
             final @StorageControllerClearFlags long flags) {
-        final CallbackResult<Void> result = new CallbackResult<Void>() {
-            @Override
-            public void sendSuccess(final Object response) {
-                complete(null);
-            }
-        };
-
         final GeckoBundle bundle = new GeckoBundle(2);
         bundle.putString("host", host);
         bundle.putLong("flags", flags);
 
-        EventDispatcher.getInstance().dispatch(
-            "GeckoView:ClearHostData", bundle, result);
-
-        return result;
+        return EventDispatcher.getInstance()
+                .queryVoid("GeckoView:ClearHostData", bundle);
     }
 
     /**

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/WebExtension.java

@@ -1216,6 +1216,13 @@ public class WebExtension {
         }
     }
 
+    /* package */ static WebExtension fromBundle(final GeckoBundle bundle) {
+        if (bundle == null) {
+            return null;
+        }
+        return new WebExtension(bundle.getBundle("extension"));
+    }
+
     /**
      * Represents either a Browser Action or a Page Action from the
      * WebExtension API.
@@ -1604,6 +1611,33 @@ public class WebExtension {
             protected ErrorCodes() {}
         }
 
+        /** These states should match gecko's AddonManager.STATE_* constants. */
+        private static class StateCodes {
+            public static final int STATE_POSTPONED = 7;
+            public static final int STATE_CANCELED = 12;
+        }
+
+        /* package */ static Throwable fromQueryException(final Throwable exception) {
+            final EventDispatcher.QueryException queryException =
+                    (EventDispatcher.QueryException) exception;
+            final Object response = queryException.data;
+            if (response instanceof GeckoBundle
+                    && ((GeckoBundle) response).containsKey("installError")) {
+                final GeckoBundle bundle = (GeckoBundle) response;
+                int errorCode = bundle.getInt("installError");
+                final int installState = bundle.getInt("state");
+                if (errorCode == 0 && installState ==
+                        StateCodes.STATE_CANCELED) {
+                    errorCode = ErrorCodes.ERROR_USER_CANCELED;
+                } else if (errorCode == 0 && installState == StateCodes.STATE_POSTPONED) {
+                    errorCode = ErrorCodes.ERROR_POSTPONED;
+                }
+                return new WebExtension.InstallException(errorCode);
+            } else {
+                return new Exception(response.toString());
+            }
+        }
+
         @Retention(RetentionPolicy.SOURCE)
         @IntDef(value = {
                 ErrorCodes.ERROR_NETWORK_FAILURE,

mobile/android/geckoview/src/main/java/org/mozilla/geckoview/WebExtensionController.java

@@ -26,9 +26,6 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.UUID;
 
-import static org.mozilla.geckoview.WebExtension.InstallException.ErrorCodes.ERROR_POSTPONED;
-import static org.mozilla.geckoview.WebExtension.InstallException.ErrorCodes.ERROR_USER_CANCELED;
-
 public class WebExtensionController {
     private final static String LOGTAG = "WebExtension";
 
@@ -74,23 +71,23 @@ public class WebExtensionController {
 
         public GeckoResult<WebExtension> get(final String id) {
             final WebExtension extension = mData.get(id);
-            if (extension == null) {
-                final WebExtensionResult result = new WebExtensionResult("extension");
-
-                final GeckoBundle bundle = new GeckoBundle(1);
-                bundle.putString("extensionId", id);
-
-                EventDispatcher.getInstance().dispatch("GeckoView:WebExtension:Get",
-                    bundle, result);
-
-                return result.then(ext -> {
-                    mData.put(ext.id, ext);
-                    mObserver.onNewExtension(ext);
-                    return GeckoResult.fromValue(ext);
-                });
+            if (extension != null) {
+                return GeckoResult.fromValue(extension);
             }
 
-            return GeckoResult.fromValue(extension);
+            final GeckoBundle bundle = new GeckoBundle(1);
+            bundle.putString("extensionId", id);
+
+            final GeckoResult<WebExtension> pending = EventDispatcher.getInstance()
+                    .queryBundle("GeckoView:WebExtension:Get", bundle)
+                    .map(WebExtension::fromBundle)
+                    .map(ext -> {
+                        mData.put(ext.id, ext);
+                        mObserver.onNewExtension(ext);
+                        return ext;
+                    });
+
+            return pending;
         }
 
         public void setObserver(final Observer observer) {
@@ -359,107 +356,21 @@ public class WebExtensionController {
         mDebuggerDelegate = delegate;
     }
 
-    private static class WebExtensionResult extends GeckoResult<WebExtension>
-            implements EventCallback {
-        /** These states should match gecko's AddonManager.STATE_* constants. */
-        private static class StateCodes {
-            public static final int STATE_POSTPONED = 7;
-            public static final int STATE_CANCELED = 12;
-        }
-
-        private final String mFieldName;
-
-        public WebExtensionResult(final String fieldName) {
-            mFieldName = fieldName;
-        }
-
-        @Override
-        public void sendSuccess(final Object response) {
-            if (response == null) {
-                complete(null);
-                return;
-            }
-            final GeckoBundle bundle = (GeckoBundle) response;
-            complete(new WebExtension(bundle.getBundle(mFieldName)));
-        }
-
-        @Override
-        public void sendError(final Object response) {
-            if (response instanceof GeckoBundle
-                    && ((GeckoBundle) response).containsKey("installError")) {
-                final GeckoBundle bundle = (GeckoBundle) response;
-                int errorCode = bundle.getInt("installError");
-                final int installState = bundle.getInt("state");
-                if (errorCode == 0 && installState == StateCodes.STATE_CANCELED) {
-                    errorCode = ERROR_USER_CANCELED;
-                } else if (errorCode == 0 && installState == StateCodes.STATE_POSTPONED) {
-                    errorCode = ERROR_POSTPONED;
-                }
-                completeExceptionally(new WebExtension.InstallException(errorCode));
-            } else {
-                completeExceptionally(new Exception(response.toString()));
-            }
-        }
-    }
-
-    private static class WebExtensionInstallResult extends WebExtensionResult {
-        private static class InstallCanceller implements GeckoResult.CancellationDelegate {
-            private static class CancelResult extends GeckoResult<Boolean>
-                    implements EventCallback {
-                @Override
-                public void sendSuccess(final Object response) {
-                    final boolean result = ((GeckoBundle) response).getBoolean("cancelled");
-                    complete(result);
-                }
-
-                @Override
-                public void sendError(final Object response) {
-                    completeExceptionally(new Exception(response.toString()));
-                }
-            }
-
-            private final String mInstallId;
-            private boolean mCancelled;
-
-            public InstallCanceller(@NonNull final String aInstallId) {
-                mInstallId = aInstallId;
-                mCancelled = false;
-            }
-
-            @Override
-            public GeckoResult<Boolean> cancel() {
-                CancelResult result = new CancelResult();
-
-                final GeckoBundle bundle = new GeckoBundle(1);
-                bundle.putString("installId", mInstallId);
-
-                EventDispatcher.getInstance().dispatch("GeckoView:WebExtension:CancelInstall",
-                        bundle, result);
-
-                return result.then(wasCancelled -> {
-                    mCancelled = wasCancelled;
-                    return GeckoResult.fromValue(wasCancelled);
-                });
-            }
-        }
-
-        /* package */ final @NonNull String installId;
-
-        private final InstallCanceller mInstallCanceller;
-
-        public WebExtensionInstallResult() {
-            super("extension");
+    private static class InstallCanceller implements GeckoResult.CancellationDelegate {
+        public final String installId;
 
+        public InstallCanceller() {
             installId = UUID.randomUUID().toString();
-            mInstallCanceller = new InstallCanceller(installId);
-            setCancellationDelegate(mInstallCanceller);
         }
 
         @Override
-        public void sendError(final Object response) {
-            if (!mInstallCanceller.mCancelled) {
-                super.sendError(response);
-            }
+        public GeckoResult<Boolean> cancel() {
+            final GeckoBundle bundle = new GeckoBundle(1);
+            bundle.putString("installId", installId);
+
+            return EventDispatcher.getInstance()
+                    .queryBundle("GeckoView:WebExtension:CancelInstall", bundle)
+                    .map(response -> response.getBoolean("cancelled"));
         }
     }
 
@@ -501,16 +412,18 @@ public class WebExtensionController {
     @NonNull
     @AnyThread
     public GeckoResult<WebExtension> install(final @NonNull String uri) {
-        WebExtensionInstallResult result = new WebExtensionInstallResult();
+        final InstallCanceller canceller = new InstallCanceller();
         final GeckoBundle bundle = new GeckoBundle(2);
         bundle.putString("locationUri", uri);
-        bundle.putString("installId", result.installId);
-        EventDispatcher.getInstance().dispatch("GeckoView:WebExtension:Install",
-                        bundle, result);
-        return result.then(extension -> {
-            registerWebExtension(extension);
-            return GeckoResult.fromValue(extension);
-        });
+        bundle.putString("installId", canceller.installId);
+
+        final GeckoResult<WebExtension> result = EventDispatcher.getInstance()
+                .queryBundle("GeckoView:WebExtension:Install", bundle)
+                .map(WebExtension::fromBundle,
+                     WebExtension.InstallException::fromQueryException)
+                .map(this::registerWebExtension);
+        result.setCancellationDelegate(canceller);
+        return result;
     }
 
     /**
@@ -526,20 +439,14 @@ public class WebExtensionController {
     public GeckoResult<WebExtension> setAllowedInPrivateBrowsing(
             final @NonNull WebExtension extension,
             final boolean allowed) {
-        final WebExtensionController.WebExtensionResult result =
-                new WebExtensionController.WebExtensionResult("extension");
-
         final GeckoBundle bundle = new GeckoBundle(2);
         bundle.putString("extensionId", extension.id);
         bundle.putBoolean("allowed", allowed);
 
-        EventDispatcher.getInstance().dispatch("GeckoView:WebExtension:SetPBAllowed",
-                bundle, result);
-
-        return result.then(newExtension -> {
-            registerWebExtension(newExtension);
-            return GeckoResult.fromValue(newExtension);
-        });
+        return EventDispatcher.getInstance()
+                .queryBundle("GeckoView:WebExtension:SetPBAllowed", bundle)
+                .map(WebExtension::fromBundle)
+                .map(this::registerWebExtension);
     }
 
     /**
@@ -567,15 +474,14 @@ public class WebExtensionController {
     @NonNull
     @AnyThread
     public GeckoResult<WebExtension> installBuiltIn(final @NonNull String uri) {
-        WebExtensionInstallResult result = new WebExtensionInstallResult();
         final GeckoBundle bundle = new GeckoBundle(1);
         bundle.putString("locationUri", uri);
-        EventDispatcher.getInstance().dispatch("GeckoView:WebExtension:InstallBuiltIn",
-                        bundle, result);
-        return result.then(extension -> {
-            registerWebExtension(extension);
-            return GeckoResult.fromValue(extension);
-        });
+
+        return EventDispatcher.getInstance()
+                .queryBundle("GeckoView:WebExtension:InstallBuiltIn", bundle)
+                .map(WebExtension::fromBundle,
+                     WebExtension.InstallException::fromQueryException)
+                .map(this::registerWebExtension);
     }
 
     /**
@@ -604,16 +510,15 @@ public class WebExtensionController {
     @AnyThread
     public GeckoResult<WebExtension> ensureBuiltIn(final @NonNull String uri,
                                                    final @Nullable String id) {
-        WebExtensionInstallResult result = new WebExtensionInstallResult();
         final GeckoBundle bundle = new GeckoBundle(2);
         bundle.putString("locationUri", uri);
         bundle.putString("webExtensionId", id);
-        EventDispatcher.getInstance().dispatch("GeckoView:WebExtension:EnsureBuiltIn",
-                bundle, result);
-        return result.then(extension -> {
-            registerWebExtension(extension);
-            return GeckoResult.fromValue(extension);
-        });
+
+        return EventDispatcher.getInstance()
+                .queryBundle("GeckoView:WebExtension:EnsureBuiltIn", bundle)
+                .map(WebExtension::fromBundle,
+                     WebExtension.InstallException::fromQueryException)
+                .map(this::registerWebExtension);
     }
 
     /**
@@ -629,23 +534,12 @@ public class WebExtensionController {
     @NonNull
     @AnyThread
     public GeckoResult<Void> uninstall(final @NonNull WebExtension extension) {
-        final CallbackResult<Void> result = new CallbackResult<Void>() {
-            @Override
-            public void sendSuccess(final Object response) {
-                complete(null);
-            }
-        };
-
         final GeckoBundle bundle = new GeckoBundle(1);
         bundle.putString("webExtensionId", extension.id);
 
-        EventDispatcher.getInstance().dispatch("GeckoView:WebExtension:Uninstall",
-                bundle, result);
-
-        return result.then(success -> {
-            unregisterWebExtension(extension);
-            return GeckoResult.fromValue(success);
-        });
+        return EventDispatcher.getInstance()
+                .queryBundle("GeckoView:WebExtension:Uninstall", bundle)
+                .accept(result -> unregisterWebExtension(extension));
     }
 
     @Retention(RetentionPolicy.SOURCE)
@@ -686,19 +580,14 @@ public class WebExtensionController {
     @NonNull
     public GeckoResult<WebExtension> enable(final @NonNull WebExtension extension,
                                             final @EnableSources int source) {
-        final WebExtensionResult result = new WebExtensionResult("extension");
-
         final GeckoBundle bundle = new GeckoBundle(2);
         bundle.putString("webExtensionId", extension.id);
         bundle.putString("source", EnableSource.toString(source));
 
-        EventDispatcher.getInstance().dispatch("GeckoView:WebExtension:Enable",
-                bundle, result);
-
-        return result.then(newExtension -> {
-            registerWebExtension(newExtension);
-            return GeckoResult.fromValue(newExtension);
-        });
+        return EventDispatcher.getInstance()
+                .queryBundle("GeckoView:WebExtension:Enable", bundle)
+                .map(WebExtension::fromBundle)
+                .map(this::registerWebExtension);
     }
 
     /**
@@ -714,19 +603,26 @@ public class WebExtensionController {
     @NonNull
     public GeckoResult<WebExtension> disable(final @NonNull WebExtension extension,
                                              final @EnableSources int source) {
-        final WebExtensionResult result = new WebExtensionResult("extension");
-
         final GeckoBundle bundle = new GeckoBundle(2);
         bundle.putString("webExtensionId", extension.id);
         bundle.putString("source", EnableSource.toString(source));
 
-        EventDispatcher.getInstance().dispatch("GeckoView:WebExtension:Disable",
-                bundle, result);
+        return EventDispatcher.getInstance()
+                .queryBundle("GeckoView:WebExtension:Disable", bundle)
+                .map(WebExtension::fromBundle)
+                .map(this::registerWebExtension);
+    }
 
-        return result.then(newExtension -> {
-            registerWebExtension(newExtension);
-            return GeckoResult.fromValue(newExtension);
-        });
+    private List<WebExtension> listFromBundle(final GeckoBundle response) {
+        final GeckoBundle[] bundles = response.getBundleArray("extensions");
+        final List<WebExtension> list = new ArrayList<>(bundles.length);
+
+        for (GeckoBundle bundle : bundles) {
+            final WebExtension extension = new WebExtension(bundle);
+            list.add(registerWebExtension(extension));
+        }
+
+        return list;
     }
 
     /**
@@ -740,27 +636,9 @@ public class WebExtensionController {
     @AnyThread
     @NonNull
     public GeckoResult<List<WebExtension>> list() {
-        final CallbackResult<List<WebExtension>> result = new CallbackResult<List<WebExtension>>() {
-            @Override
-            public void sendSuccess(final Object response) {
-                final GeckoBundle[] bundles = ((GeckoBundle) response)
-                        .getBundleArray("extensions");
-                final List<WebExtension> list = new ArrayList<>(bundles.length);
-
-                for (GeckoBundle bundle : bundles) {
-                    final WebExtension extension = new WebExtension(bundle);
-                    registerWebExtension(extension);
-                    list.add(extension);
-                }
-
-                complete(list);
-            }
-        };
-
-        EventDispatcher.getInstance().dispatch("GeckoView:WebExtension:List",
-                null, result);
-
-        return result;
+        return EventDispatcher.getInstance()
+                .queryBundle("GeckoView:WebExtension:List")
+                .map(this::listFromBundle);
     }
 
     /**
@@ -788,20 +666,14 @@ public class WebExtensionController {
     @AnyThread
     @NonNull
     public GeckoResult<WebExtension> update(final @NonNull WebExtension extension) {
-        final WebExtensionResult result = new WebExtensionResult("extension");
-
         final GeckoBundle bundle = new GeckoBundle(1);
         bundle.putString("webExtensionId", extension.id);
 
-        EventDispatcher.getInstance().dispatch("GeckoView:WebExtension:Update",
-                bundle, result);
-
-        return result.then(newExtension -> {
-            if (newExtension != null) {
-                registerWebExtension(newExtension);
-            }
-            return GeckoResult.fromValue(newExtension);
-        });
+        return EventDispatcher.getInstance()
+                .queryBundle("GeckoView:WebExtension:Update", bundle)
+                .map(WebExtension::fromBundle,
+                     WebExtension.InstallException::fromQueryException)
+                .map(this::registerWebExtension);
     }
 
     /* package */ WebExtensionController(final GeckoRuntime runtime) {
@@ -814,9 +686,12 @@ public class WebExtensionController {
         mDownloads = new HashMap<>();
     }
 
-    /* package */ void registerWebExtension(final WebExtension webExtension) {
-        webExtension.setDelegateController(new DelegateController(webExtension));
-        mExtensions.update(webExtension.id, webExtension);
+    /* package */ WebExtension registerWebExtension(final WebExtension webExtension) {
+        if (webExtension != null) {
+            webExtension.setDelegateController(new DelegateController(webExtension));
+            mExtensions.update(webExtension.id, webExtension);
+        }
+        return webExtension;
     }
 
     /* package */ void handleMessage(final String event, final GeckoBundle bundle,