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[MessageHandler] Convert the code to a proper class

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This commit is contained in:
Jonas Jenwald 2019-10-30 22:05:25 +01:00
parent 5d5733c0a7
commit 0293222b96
1 changed files with 100 additions and 88 deletions
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188
src/shared/message_handler.js
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@ -61,82 +61,82 @@ function wrapReason(reason) {
} }
} }
function MessageHandler(sourceName, targetName, comObj) { class MessageHandler {
this.sourceName = sourceName; constructor(sourceName, targetName, comObj) {
this.targetName = targetName; this.sourceName = sourceName;
this.comObj = comObj; this.targetName = targetName;
this.callbackId = 1; this.comObj = comObj;
this.streamId = 1; this.callbackId = 1;
this.postMessageTransfers = true; this.streamId = 1;
this.streamSinks = Object.create(null); this.postMessageTransfers = true;
this.streamControllers = Object.create(null); this.streamSinks = Object.create(null);
this.callbackCapabilities = Object.create(null); this.streamControllers = Object.create(null);
this.actionHandler = Object.create(null); this.callbackCapabilities = Object.create(null);
this.actionHandler = Object.create(null);
this._onComObjOnMessage = (event) => { this._onComObjOnMessage = (event) => {
const data = event.data; const data = event.data;
if (data.targetName !== this.sourceName) { if (data.targetName !== this.sourceName) {
return; return;
}
if (data.stream) {
this._processStreamMessage(data);
return;
}
if (data.callback) {
const callbackId = data.callbackId;
const capability = this.callbackCapabilities[callbackId];
if (!capability) {
throw new Error(`Cannot resolve callback ${callbackId}`);
} }
delete this.callbackCapabilities[callbackId]; if (data.stream) {
this._processStreamMessage(data);
if (data.callback === CallbackKind.DATA) { return;
capability.resolve(data.data);
} else if (data.callback === CallbackKind.ERROR) {
capability.reject(wrapReason(data.reason));
} else {
throw new Error('Unexpected callback case');
} }
return; if (data.callback) {
} const callbackId = data.callbackId;
const action = this.actionHandler[data.action]; const capability = this.callbackCapabilities[callbackId];
if (!action) { if (!capability) {
throw new Error(`Unknown action from worker: ${data.action}`); throw new Error(`Cannot resolve callback ${callbackId}`);
} }
if (data.callbackId) { delete this.callbackCapabilities[callbackId];
const sourceName = this.sourceName;
const targetName = data.sourceName; if (data.callback === CallbackKind.DATA) {
new Promise(function(resolve) { capability.resolve(data.data);
resolve(action(data.data)); } else if (data.callback === CallbackKind.ERROR) {
}).then(function(result) { capability.reject(wrapReason(data.reason));
comObj.postMessage({ } else {
sourceName, throw new Error('Unexpected callback case');
targetName, }
callback: CallbackKind.DATA, return;
callbackId: data.callbackId, }
data: result, const action = this.actionHandler[data.action];
}); if (!action) {
}, function(reason) { throw new Error(`Unknown action from worker: ${data.action}`);
comObj.postMessage({ }
sourceName, if (data.callbackId) {
targetName, const sourceName = this.sourceName;
callback: CallbackKind.ERROR, const targetName = data.sourceName;
callbackId: data.callbackId, new Promise(function(resolve) {
reason: wrapReason(reason), resolve(action(data.data));
}); }).then(function(result) {
}); comObj.postMessage({
return; sourceName,
} targetName,
if (data.streamId) { callback: CallbackKind.DATA,
this._createStreamSink(data); callbackId: data.callbackId,
return; data: result,
} });
action(data.data); }, function(reason) {
}; comObj.postMessage({
comObj.addEventListener('message', this._onComObjOnMessage); sourceName,
} targetName,
callback: CallbackKind.ERROR,
callbackId: data.callbackId,
reason: wrapReason(reason),
});
});
return;
}
if (data.streamId) {
this._createStreamSink(data);
return;
}
action(data.data);
};
comObj.addEventListener('message', this._onComObjOnMessage);
}
MessageHandler.prototype = {
on(actionName, handler) { on(actionName, handler) {
if (typeof PDFJSDev === 'undefined' || if (typeof PDFJSDev === 'undefined' ||
PDFJSDev.test('!PRODUCTION || TESTING')) { PDFJSDev.test('!PRODUCTION || TESTING')) {
@ -148,7 +148,8 @@ MessageHandler.prototype = {
throw new Error(`There is already an actionName called "${actionName}"`); throw new Error(`There is already an actionName called "${actionName}"`);
} }
ah[actionName] = handler; ah[actionName] = handler;
}, }
/** /**
* Sends a message to the comObj to invoke the action with the supplied data. * Sends a message to the comObj to invoke the action with the supplied data.
* @param {string} actionName - Action to call. * @param {string} actionName - Action to call.
@ -156,13 +157,14 @@ MessageHandler.prototype = {
* @param {Array} [transfers] - List of transfers/ArrayBuffers. * @param {Array} [transfers] - List of transfers/ArrayBuffers.
*/ */
send(actionName, data, transfers) { send(actionName, data, transfers) {
this.postMessage({ this._postMessage({
sourceName: this.sourceName, sourceName: this.sourceName,
targetName: this.targetName, targetName: this.targetName,
action: actionName, action: actionName,
data, data,
}, transfers); }, transfers);
}, }
/** /**
* Sends a message to the comObj to invoke the action with the supplied data. * Sends a message to the comObj to invoke the action with the supplied data.
* Expects that the other side will callback with the response. * Expects that the other side will callback with the response.
@ -176,7 +178,7 @@ MessageHandler.prototype = {
const capability = createPromiseCapability(); const capability = createPromiseCapability();
this.callbackCapabilities[callbackId] = capability; this.callbackCapabilities[callbackId] = capability;
try { try {
this.postMessage({ this._postMessage({
sourceName: this.sourceName, sourceName: this.sourceName,
targetName: this.targetName, targetName: this.targetName,
action: actionName, action: actionName,
@ -187,7 +189,8 @@ MessageHandler.prototype = {
capability.reject(ex); capability.reject(ex);
} }
return capability.promise; return capability.promise;
}, }
/** /**
* Sends a message to the comObj to invoke the action with the supplied data. * Sends a message to the comObj to invoke the action with the supplied data.
* Expect that the other side will callback to signal 'start_complete'. * Expect that the other side will callback to signal 'start_complete'.
@ -214,7 +217,7 @@ MessageHandler.prototype = {
cancelCall: null, cancelCall: null,
isClosed: false, isClosed: false,
}; };
this.postMessage({ this._postMessage({
sourceName, sourceName,
targetName, targetName,
action: actionName, action: actionName,
@ -257,8 +260,11 @@ MessageHandler.prototype = {
return cancelCapability.promise; return cancelCapability.promise;
}, },
}, queueingStrategy); }, queueingStrategy);
}, }
/**
* @private
*/
_createStreamSink(data) { _createStreamSink(data) {
const self = this; const self = this;
const action = this.actionHandler[data.action]; const action = this.actionHandler[data.action];
@ -281,7 +287,7 @@ MessageHandler.prototype = {
this.sinkCapability = createPromiseCapability(); this.sinkCapability = createPromiseCapability();
this.ready = this.sinkCapability.promise; this.ready = this.sinkCapability.promise;
} }
self.postMessage({ self._postMessage({
sourceName, sourceName,
targetName, targetName,
stream: StreamKind.ENQUEUE, stream: StreamKind.ENQUEUE,
@ -349,8 +355,11 @@ MessageHandler.prototype = {
reason: wrapReason(reason), reason: wrapReason(reason),
}); });
}); });
}, }
/**
* @private
*/
_processStreamMessage(data) { _processStreamMessage(data) {
const streamId = data.streamId; const streamId = data.streamId;
const sourceName = this.sourceName; const sourceName = this.sourceName;
@ -482,8 +491,11 @@ MessageHandler.prototype = {
default: default:
throw new Error('Unexpected stream case'); throw new Error('Unexpected stream case');
} }
}, }
/**
* @private
*/
async _deleteStreamController(streamId) { async _deleteStreamController(streamId) {
// Delete the `streamController` only when the start, pull, and cancel // Delete the `streamController` only when the start, pull, and cancel
// capabilities have settled, to prevent `TypeError`s. // capabilities have settled, to prevent `TypeError`s.
@ -495,26 +507,26 @@ MessageHandler.prototype = {
return capability && capability.promise.catch(function() { }); return capability && capability.promise.catch(function() { });
})); }));
delete this.streamControllers[streamId]; delete this.streamControllers[streamId];
}, }
/** /**
* Sends raw message to the comObj. * Sends raw message to the comObj.
* @private
* @param {Object} message - Raw message. * @param {Object} message - Raw message.
* @param transfers List of transfers/ArrayBuffers, or undefined. * @param transfers List of transfers/ArrayBuffers, or undefined.
* @private
*/ */
postMessage(message, transfers) { _postMessage(message, transfers) {
if (transfers && this.postMessageTransfers) { if (transfers && this.postMessageTransfers) {
this.comObj.postMessage(message, transfers); this.comObj.postMessage(message, transfers);
} else { } else {
this.comObj.postMessage(message); this.comObj.postMessage(message);
} }
}, }
destroy() { destroy() {
this.comObj.removeEventListener('message', this._onComObjOnMessage); this.comObj.removeEventListener('message', this._onComObjOnMessage);
}, }
}; }
export { export {
MessageHandler, MessageHandler,