Message handler refactor (#660)

* Refactor searchQueryUpdate action

* Use standard message handler style

* Use name "promiseOrResult" for consistency

* Use standard message handler convention for Yomichan message handlers

* Use common message handler invoker

5 files changed, 80 insertions, 86 deletions

diff --git a/ext/bg/js/backend.js b/ext/bg/js/backend.js
index 6e594f9b..07c32fa2 100644
--- a/ext/bg/js/backend.js
+++ b/ext/bg/js/backend.js
@@ -294,28 +294,16 @@ class Backend {
         const messageHandler = this._messageHandlers.get(action);
         if (typeof messageHandler === 'undefined') { return false; }
 
-        const {handler, async, contentScript} = messageHandler;
-
-        try {
-            if (!contentScript) {
+        if (!messageHandler.contentScript) {
+            try {
                 this._validatePrivilegedMessageSender(sender);
-            }
-
-            const promiseOrResult = handler(params, sender);
-            if (async) {
-                promiseOrResult.then(
-                    (result) => callback({result}),
-                    (error) => callback({error: errorToJson(error)})
-                );
-                return true;
-            } else {
-                callback({result: promiseOrResult});
+            } catch (error) {
+                callback({error: errorToJson(error)});
                 return false;
             }
-        } catch (error) {
-            callback({error: errorToJson(error)});
-            return false;
         }
+
+        return yomichan.invokeMessageHandler(messageHandler, params, callback, sender);
     }
 
     _onConnect(port) {
@@ -814,11 +802,7 @@ class Backend {
             if (tab !== null) {
                 await this._focusTab(tab);
                 if (queryParams.query) {
-                    await new Promise((resolve) => chrome.tabs.sendMessage(
-                        tab.id,
-                        {action: 'searchQueryUpdate', params: {text: queryParams.query}},
-                        resolve
-                    ));
+                    await this._updateSearchQuery(tab.id, queryParams.query);
                 }
                 return true;
             }
@@ -882,6 +866,21 @@ class Backend {
 
     // Utilities
 
+    _updateSearchQuery(tabId, text) {
+        new Promise((resolve, reject) => {
+            const callback = (response) => {
+                try {
+                    resolve(yomichan.getMessageResponseResult(response));
+                } catch (error) {
+                    reject(error);
+                }
+            };
+
+            const message = {action: 'updateSearchQuery', params: {text}};
+            chrome.tabs.sendMessage(tabId, message, callback);
+        });
+    }
+
     _sendMessageAllTabs(action, params={}) {
         const callback = () => this._checkLastError(chrome.runtime.lastError);
         chrome.tabs.query({}, (tabs) => {
@@ -1286,11 +1285,10 @@ class Backend {
         return new Promise((resolve) => {
             chrome.tabs.sendMessage(tab.id, {action: 'getUrl'}, {frameId: 0}, (response) => {
                 let url = null;
-                if (!chrome.runtime.lastError) {
-                    url = (response !== null && typeof response === 'object' && !Array.isArray(response) ? response.url : null);
-                    if (url !== null && typeof url !== 'string') {
-                        url = null;
-                    }
+                try {
+                    url = yomichan.getMessageResponseResult(response);
+                } catch (error) {
+                    // NOP
                 }
                 resolve({tab, url});
             });
diff --git a/ext/bg/js/search.js b/ext/bg/js/search.js
index 9bbc66f2..52fc19f8 100644
--- a/ext/bg/js/search.js
+++ b/ext/bg/js/search.js
@@ -61,7 +61,7 @@ class DisplaySearch extends Display {
             ['Shift', new Set()]
         ]);
         this._runtimeMessageHandlers = new Map([
-            ['searchQueryUpdate', this._onExternalSearchUpdate.bind(this)]
+            ['updateSearchQuery', {async: false, handler: this._onExternalSearchUpdate.bind(this)}]
         ]);
 
         this.setOptionsContext({
@@ -206,12 +206,9 @@ class DisplaySearch extends Display {
     }
 
     _onRuntimeMessage({action, params}, sender, callback) {
-        const handler = this._runtimeMessageHandlers.get(action);
-        if (typeof handler !== 'function') { return false; }
-
-        const result = handler(params, sender);
-        callback(result);
-        return false;
+        const messageHandler = this._runtimeMessageHandlers.get(action);
+        if (typeof messageHandler === 'undefined') { return false; }
+        return yomichan.invokeMessageHandler(messageHandler, params, callback, sender);
     }
 
     _onCopy() {
diff --git a/ext/fg/js/frontend.js b/ext/fg/js/frontend.js
index 1618fa12..aa03d4b5 100644
--- a/ext/fg/js/frontend.js
+++ b/ext/fg/js/frontend.js
@@ -211,25 +211,7 @@ class Frontend {
     _onRuntimeMessage({action, params}, sender, callback) {
         const messageHandler = this._runtimeMessageHandlers.get(action);
         if (typeof messageHandler === 'undefined') { return false; }
-
-        const {handler, async} = messageHandler;
-
-        try {
-            const promiseOrResult = handler(params, sender);
-            if (async) {
-                promiseOrResult.then(
-                    (result) => callback({result}),
-                    (error) => callback({error: errorToJson(error)})
-                );
-                return true;
-            } else {
-                callback({result: promiseOrResult});
-                return false;
-            }
-        } catch (error) {
-            callback({error: errorToJson(error)});
-            return false;
-        }
+        return yomichan.invokeMessageHandler(messageHandler, params, callback, sender);
     }
 
     _onZoomChanged({newZoomFactor}) {
diff --git a/ext/mixed/js/comm.js b/ext/mixed/js/comm.js
index 182400e3..1516a98f 100644
--- a/ext/mixed/js/comm.js
+++ b/ext/mixed/js/comm.js
@@ -166,31 +166,14 @@ class CrossFrameAPIPort extends EventDispatcher {
     // Invocation
 
     _onInvoke(id, {action, params}) {
+        const callback = (response) => this._sendResponse({type: 'result', id, data: response});
         const messageHandler = this._messageHandlers.get(action);
         if (typeof messageHandler === 'undefined') {
-            this._sendError(id, new Error(`Unknown action: ${action}`));
-            return;
+            callback({error: new Error(`Unknown action: ${action}`)});
+            return false;
         }
-
-        let {handler, async} = messageHandler;
-
         this._sendAck(id);
-        try {
-            let result = handler(params);
-            if (async === 'dynamic') {
-                ({async, result} = result);
-            }
-            if (async) {
-                result.then(
-                    (result2) => this._sendResult(id, result2),
-                    (error2) => this._sendError(id, error2)
-                );
-            } else {
-                this._sendResult(id, result);
-            }
-        } catch (error) {
-            this._sendError(id, error);
-        }
+        return yomichan.invokeMessageHandler(messageHandler, params, callback);
     }
 
     _sendResponse(data) {
diff --git a/ext/mixed/js/yomichan.js b/ext/mixed/js/yomichan.js
index d921a5a2..7fffbaa6 100644
--- a/ext/mixed/js/yomichan.js
+++ b/ext/mixed/js/yomichan.js
@@ -54,10 +54,10 @@ const yomichan = (() => {
             this._isBackendPreparedPromiseResolve = resolve;
 
             this._messageHandlers = new Map([
-                ['backendPrepared', this._onMessageBackendPrepared.bind(this)],
-                ['getUrl',          this._onMessageGetUrl.bind(this)],
-                ['optionsUpdated',  this._onMessageOptionsUpdated.bind(this)],
-                ['zoomChanged',     this._onMessageZoomChanged.bind(this)]
+                ['backendPrepared', {async: false, handler: this._onMessageBackendPrepared.bind(this)}],
+                ['getUrl',          {async: false, handler: this._onMessageGetUrl.bind(this)}],
+                ['optionsUpdated',  {async: false, handler: this._onMessageOptionsUpdated.bind(this)}],
+                ['zoomChanged',     {async: false, handler: this._onMessageZoomChanged.bind(this)}]
             ]);
         }
 
@@ -210,6 +210,43 @@ const yomichan = (() => {
             }
         }
 
+        getMessageResponseResult(response) {
+            let error = chrome.runtime.lastError;
+            if (error) {
+                throw new Error(error.message);
+            }
+            if (!isObject(response)) {
+                throw new Error('Tab did not respond');
+            }
+            error = response.error;
+            if (error) {
+                throw jsonToError(error);
+            }
+            return response.result;
+        }
+
+        invokeMessageHandler({handler, async}, params, callback, ...extraArgs) {
+            try {
+                let promiseOrResult = handler(params, ...extraArgs);
+                if (async === 'dynamic') {
+                    ({async, result: promiseOrResult} = promiseOrResult);
+                }
+                if (async) {
+                    promiseOrResult.then(
+                        (result) => { callback({result}); },
+                        (error) => { callback({error: errorToJson(error)}); }
+                    );
+                    return true;
+                } else {
+                    callback({result: promiseOrResult});
+                    return false;
+                }
+            } catch (error) {
+                callback({error: errorToJson(error)});
+                return false;
+            }
+        }
+
         // Private
 
         _onExtensionUnloaded(error) {
@@ -222,16 +259,13 @@ const yomichan = (() => {
         }
 
         _getLogContext() {
-            return {url: this._getUrl()};
+            return this._getUrl();
         }
 
         _onMessage({action, params}, sender, callback) {
-            const handler = this._messageHandlers.get(action);
-            if (typeof handler !== 'function') { return false; }
-
-            const result = handler(params, sender);
-            callback(result);
-            return false;
+            const messageHandler = this._messageHandlers.get(action);
+            if (typeof messageHandler === 'undefined') { return false; }
+            return this.invokeMessageHandler(messageHandler, params, callback, sender);
         }
 
         _onMessageBackendPrepared() {