Reland of Timeline: extract and rename TracingModelLoader into a file of its own

third_party/WebKit/Source/devtools/front_end/timeline/TimelineLoader.js

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @constructor
+ * @implements {WebInspector.OutputStream}
+ * @param {!WebInspector.TimelineModel} model
+ * @param {!WebInspector.Progress} progress
+ * @param {function()=} canceledCallback
+ */
+WebInspector.TimelineLoader = function(model, progress, canceledCallback)
+{
+    this._model = model;
+
+    this._canceledCallback = canceledCallback;
+    this._progress = progress;
+    this._progress.setTitle(WebInspector.UIString("Loading"));
+    this._progress.setTotalWork(WebInspector.TimelineLoader._totalProgress);  // Unknown, will loop the values.
+
+    this._state = WebInspector.TimelineLoader.State.Initial;
+    this._buffer = "";
+    this._firstChunk = true;
+    this._wasCanceledOnce = false;
+
+    this._loadedBytes = 0;
+    this._jsonTokenizer = new WebInspector.TextUtils.BalancedJSONTokenizer(this._writeBalancedJSON.bind(this), true);
+}
+
+/**
+ * @param {!WebInspector.TimelineModel} model
+ * @param {!File} file
+ * @param {!WebInspector.Progress} progress
+ */
+WebInspector.TimelineLoader.loadFromFile = function(model, file, progress)
+{
+    var delegate = new WebInspector.TimelineModelLoadFromFileDelegate(model, progress);
+    var fileReader = WebInspector.TimelineLoader._createFileReader(file, delegate);
+    var loader = new WebInspector.TimelineLoader(model, new WebInspector.ProgressProxy(null), fileReader.cancel.bind(fileReader));
+    fileReader.start(loader);
+}
+
+/**
+ * @param {!WebInspector.TimelineModel} model
+ * @param {string} url
+ * @param {!WebInspector.Progress} progress
+ */
+WebInspector.TimelineLoader.loadFromURL = function(model, url, progress)
+{
+    var stream = new WebInspector.TimelineLoader(model, progress);
+    WebInspector.ResourceLoader.loadAsStream(url, null, stream);
+}
+
+/**
+ * @param {!File} file
+ * @param {!WebInspector.OutputStreamDelegate} delegate
+ * @return {!WebInspector.ChunkedReader}
+ */
+WebInspector.TimelineLoader._createFileReader = function(file, delegate)
+{
+    return new WebInspector.ChunkedFileReader(file, WebInspector.TimelineModel.TransferChunkLengthBytes, delegate);
+}
+
+
+WebInspector.TimelineLoader._totalProgress = 100000;
+
+WebInspector.TimelineLoader.State = {
+    Initial: "Initial",
+    LookingForEvents: "LookingForEvents",
+    ReadingEvents: "ReadingEvents"
+}
+
+WebInspector.TimelineLoader.prototype = {
+    /**
+     * @override
+     * @param {string} chunk
+     */
+    write: function(chunk)
+    {
+        this._loadedBytes += chunk.length;
+        if (this._progress.isCanceled() && !this._wasCanceledOnce) {
+            this._wasCanceled = true;
+            this._reportErrorAndCancelLoading();
+            return;
+        }
+        this._progress.setWorked(this._loadedBytes % WebInspector.TimelineLoader._totalProgress,
+                                 WebInspector.UIString("Loaded %s", Number.bytesToString(this._loadedBytes)));
+        if (this._state === WebInspector.TimelineLoader.State.Initial) {
+            if (chunk[0] === "{")
+                this._state = WebInspector.TimelineLoader.State.LookingForEvents;
+            else if (chunk[0] === "[")
+                this._state = WebInspector.TimelineLoader.State.ReadingEvents;
+            else {
+                this._reportErrorAndCancelLoading(WebInspector.UIString("Malformed timeline data: Unknown JSON format"));
+                return;
+            }
+        }
+
+        if (this._state === WebInspector.TimelineLoader.State.LookingForEvents) {
+            var objectName = "\"traceEvents\":";
+            var startPos = this._buffer.length - objectName.length;
+            this._buffer += chunk;
+            var pos = this._buffer.indexOf(objectName, startPos);
+            if (pos === -1)
+                return;
+            chunk = this._buffer.slice(pos + objectName.length)
+            this._state = WebInspector.TimelineLoader.State.ReadingEvents;
+        }
+
+        this._jsonTokenizer.write(chunk);
+    },
+
+    /**
+     * @param {string} data
+     */
+    _writeBalancedJSON: function(data)
+    {
+        var json = data + "]";
+
+        if (this._firstChunk) {
+            this._model.startCollectingTraceEvents(true);
+        } else {
+            var commaIndex = json.indexOf(",");
+            if (commaIndex !== -1)
+                json = json.slice(commaIndex + 1);
+            json = "[" + json;
+        }
+
+        var items;
+        try {
+            items = /** @type {!Array.<!WebInspector.TracingManager.EventPayload>} */ (JSON.parse(json));
+        } catch (e) {
+            this._reportErrorAndCancelLoading(WebInspector.UIString("Malformed timeline data: %s", e.toString()));
+            return;
+        }
+
+        if (this._firstChunk) {
+            this._firstChunk = false;
+            if (this._looksLikeAppVersion(items[0])) {
+                this._reportErrorAndCancelLoading(WebInspector.UIString("Legacy Timeline format is not supported."));
+                return;
+            }
+        }
+
+        try {
+            this._model.traceEventsCollected(items);
+        } catch(e) {
+            this._reportErrorAndCancelLoading(WebInspector.UIString("Malformed timeline data: %s", e.toString()));
+            return;
+        }
+    },
+
+    /**
+     * @param {string=} message
+     */
+    _reportErrorAndCancelLoading: function(message)
+    {
+        if (message)
+            WebInspector.console.error(message);
+        this._model.tracingComplete();
+        this._model.reset();
+        if (this._canceledCallback)
+            this._canceledCallback();
+        this._progress.done();
+    },
+
+    /**
+     * @param {*} item
+     * @return {boolean}
+     */
+    _looksLikeAppVersion: function(item)
+    {
+        return typeof item === "string" && item.indexOf("Chrome") !== -1;
+    },
+
+    /**
+     * @override
+     */
+    close: function()
+    {
+        this._model._loadedFromFile = true;
+        this._model.tracingComplete();
+        if (this._progress)
+            this._progress.done();
+    }
+}
+
+/**
+ * @constructor
+ * @implements {WebInspector.OutputStreamDelegate}
+ * @param {!WebInspector.TimelineModel} model
+ * @param {!WebInspector.Progress} progress
+ */
+WebInspector.TimelineModelLoadFromFileDelegate = function(model, progress)
+{
+    this._model = model;
+    this._progress = progress;
+}
+
+WebInspector.TimelineModelLoadFromFileDelegate.prototype = {
+    /**
+     * @override
+     */
+    onTransferStarted: function()
+    {
+        this._progress.setTitle(WebInspector.UIString("Loading\u2026"));
+    },
+
+    /**
+     * @override
+     * @param {!WebInspector.ChunkedReader} reader
+     */
+    onChunkTransferred: function(reader)
+    {
+        if (this._progress.isCanceled()) {
+            reader.cancel();
+            this._progress.done();
+            this._model.reset();
+            return;
+        }
+
+        var totalSize = reader.fileSize();
+        if (totalSize) {
+            this._progress.setTotalWork(totalSize);
+            this._progress.setWorked(reader.loadedSize());
+        }
+    },
+
+    /**
+     * @override
+     */
+    onTransferFinished: function()
+    {
+        this._progress.done();
+    },
+
+    /**
+     * @override
+     * @param {!WebInspector.ChunkedReader} reader
+     * @param {!Event} event
+     */
+    onError: function(reader, event)
+    {
+        this._progress.done();
+        this._model.reset();
+        switch (event.target.error.code) {
+        case FileError.NOT_FOUND_ERR:
+            WebInspector.console.error(WebInspector.UIString("File \"%s\" not found.", reader.fileName()));
+            break;
+        case FileError.NOT_READABLE_ERR:
+            WebInspector.console.error(WebInspector.UIString("File \"%s\" is not readable", reader.fileName()));
+            break;
+        case FileError.ABORT_ERR:
+            break;
+        default:
+            WebInspector.console.error(WebInspector.UIString("An error occurred while reading the file \"%s\"", reader.fileName()));
+        }
+    }
+}
+
+/**
+ * @constructor
+ * @param {!WebInspector.OutputStream} stream
+ * @implements {WebInspector.OutputStreamDelegate}
+ */
+WebInspector.TracingTimelineSaver = function(stream)
+{
+    this._stream = stream;
+}
+
+WebInspector.TracingTimelineSaver.prototype = {
+    /**
+     * @override
+     */
+    onTransferStarted: function()
+    {
+        this._stream.write("[");
+    },
+
+    /**
+     * @override
+     */
+    onTransferFinished: function()
+    {
+        this._stream.write("]");
+    },
+
+    /**
+     * @override
+     * @param {!WebInspector.ChunkedReader} reader
+     */
+    onChunkTransferred: function(reader) { },
+
+    /**
+     * @override
+     * @param {!WebInspector.ChunkedReader} reader
+     * @param {!Event} event
+     */
+    onError: function(reader, event) { }
+}