1 files changed, 173 insertions, 0 deletions
diff --git a/devtools/client/performance/modules/io.js b/devtools/client/performance/modules/io.js
new file mode 100644
index 0000000000..97fb16dc41
--- /dev/null
+++ b/devtools/client/performance/modules/io.js
@@ -0,0 +1,173 @@
+/* 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/. */
+"use strict";
+
+const { Cc, Ci } = require("chrome");
+
+const RecordingUtils = require("devtools/shared/performance/recording-utils");
+const { FileUtils } = require("resource://gre/modules/FileUtils.jsm");
+const { NetUtil } = require("resource://gre/modules/NetUtil.jsm");
+
+// This identifier string is used to tentatively ascertain whether or not
+// a JSON loaded from disk is actually something generated by this tool.
+// It isn't, of course, a definitive verification, but a Good Enough™
+// approximation before continuing the import. Don't localize this.
+const PERF_TOOL_SERIALIZER_IDENTIFIER = "Recorded Performance Data";
+const PERF_TOOL_SERIALIZER_LEGACY_VERSION = 1;
+const PERF_TOOL_SERIALIZER_CURRENT_VERSION = 2;
+
+/**
+ * Helpers for importing/exporting JSON.
+ */
+
+/**
+ * Gets a nsIScriptableUnicodeConverter instance with a default UTF-8 charset.
+ * @return object
+ */
+function getUnicodeConverter() {
+  const cname = "@mozilla.org/intl/scriptableunicodeconverter";
+  const converter = Cc[cname].createInstance(Ci.nsIScriptableUnicodeConverter);
+  converter.charset = "UTF-8";
+  return converter;
+}
+
+/**
+ * Saves a recording as JSON to a file. The provided data is assumed to be
+ * acyclical, so that it can be properly serialized.
+ *
+ * @param object recordingData
+ *        The recording data to stream as JSON.
+ * @param nsIFile file
+ *        The file to stream the data into.
+ * @return object
+ *         A promise that is resolved once streaming finishes, or rejected
+ *         if there was an error.
+ */
+function saveRecordingToFile(recordingData, file) {
+  recordingData.fileType = PERF_TOOL_SERIALIZER_IDENTIFIER;
+  recordingData.version = PERF_TOOL_SERIALIZER_CURRENT_VERSION;
+
+  const string = JSON.stringify(recordingData);
+  const inputStream = getUnicodeConverter().convertToInputStream(string);
+  const outputStream = FileUtils.openSafeFileOutputStream(file);
+
+  return new Promise(resolve => {
+    NetUtil.asyncCopy(inputStream, outputStream, resolve);
+  });
+}
+
+/**
+ * Loads a recording stored as JSON from a file.
+ *
+ * @param nsIFile file
+ *        The file to import the data from.
+ * @return object
+ *         A promise that is resolved once importing finishes, or rejected
+ *         if there was an error.
+ */
+function loadRecordingFromFile(file) {
+  const channel = NetUtil.newChannel({
+    uri: NetUtil.newURI(file),
+    loadUsingSystemPrincipal: true,
+  });
+
+  channel.contentType = "text/plain";
+
+  return new Promise((resolve, reject) => {
+    NetUtil.asyncFetch(channel, inputStream => {
+      let recordingData;
+
+      try {
+        const string = NetUtil.readInputStreamToString(
+          inputStream,
+          inputStream.available()
+        );
+        recordingData = JSON.parse(string);
+      } catch (e) {
+        reject(new Error("Could not read recording data file."));
+        return;
+      }
+
+      if (recordingData.fileType != PERF_TOOL_SERIALIZER_IDENTIFIER) {
+        reject(new Error("Unrecognized recording data file."));
+        return;
+      }
+
+      if (!isValidSerializerVersion(recordingData.version)) {
+        reject(new Error("Unsupported recording data file version."));
+        return;
+      }
+
+      if (recordingData.version === PERF_TOOL_SERIALIZER_LEGACY_VERSION) {
+        recordingData = convertLegacyData(recordingData);
+      }
+
+      if (recordingData.profile.meta.version === 2) {
+        RecordingUtils.deflateProfile(recordingData.profile);
+      }
+
+      // If the recording has no label, set it to be the
+      // filename without its extension.
+      if (!recordingData.label) {
+        recordingData.label = file.leafName.replace(/\.[^.]+$/, "");
+      }
+
+      resolve(recordingData);
+    });
+  });
+}
+
+/**
+ * Returns a boolean indicating whether or not the passed in `version`
+ * is supported by this serializer.
+ *
+ * @param number version
+ * @return boolean
+ */
+function isValidSerializerVersion(version) {
+  return !!~[
+    PERF_TOOL_SERIALIZER_LEGACY_VERSION,
+    PERF_TOOL_SERIALIZER_CURRENT_VERSION,
+  ].indexOf(version);
+}
+
+/**
+ * Takes recording data (with version `1`, from the original profiler tool),
+ * and massages the data to be line with the current performance tool's
+ * property names and values.
+ *
+ * @param object legacyData
+ * @return object
+ */
+function convertLegacyData(legacyData) {
+  const { profilerData, ticksData, recordingDuration } = legacyData;
+
+  // The `profilerData` and `ticksData` stay, but the previously unrecorded
+  // fields just are empty arrays or objects.
+  const data = {
+    label: profilerData.profilerLabel,
+    duration: recordingDuration,
+    markers: [],
+    frames: [],
+    memory: [],
+    ticks: ticksData,
+    allocations: { sites: [], timestamps: [], frames: [], sizes: [] },
+    profile: profilerData.profile,
+    // Fake a configuration object here if there's tick data,
+    // so that it can be rendered.
+    configuration: {
+      withTicks: !!ticksData.length,
+      withMarkers: false,
+      withMemory: false,
+      withAllocations: false,
+    },
+    systemHost: {},
+    systemClient: {},
+  };
+
+  return data;
+}
+
+exports.saveRecordingToFile = saveRecordingToFile;
+exports.loadRecordingFromFile = loadRecordingFromFile;