Back out d52a31584c8a (bug 763525) to investigate the effects on TestStartupCache bustage on a CLOSED TREE

toolkit/components/telemetry/Telemetry.cpp

@@ -1189,6 +1189,346 @@ TelemetryImpl::GetHistogramById(const nsACString &name, JSContext *cx, jsval *re
   return WrapAndReturnHistogram(h, cx, ret);
 }
 
+class TelemetrySessionData : public nsITelemetrySessionData
+{
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSITELEMETRYSESSIONDATA
+
+public:
+  static nsresult LoadFromDisk(nsIFile *, TelemetrySessionData **ptr);
+  static nsresult SaveToDisk(nsIFile *, const nsACString &uuid);
+
+  TelemetrySessionData(const char *uuid);
+  ~TelemetrySessionData();
+
+private:
+  typedef nsBaseHashtableET<nsUint32HashKey, Histogram::SampleSet> EntryType;
+  typedef AutoHashtable<EntryType> SessionMapType;
+  static bool SampleReflector(EntryType *entry, JSContext *cx, JSObject *obj);
+  SessionMapType mSampleSetMap;
+  nsCString mUUID;
+
+  bool DeserializeHistogramData(Pickle &pickle, void **iter);
+  static bool SerializeHistogramData(Pickle &pickle);
+
+  // The file format version.  Should be incremented whenever we change
+  // how individual SampleSets are stored in the file.
+  static const unsigned int sVersion = 1;
+};
+
+NS_IMPL_THREADSAFE_ISUPPORTS1(TelemetrySessionData, nsITelemetrySessionData)
+
+TelemetrySessionData::TelemetrySessionData(const char *uuid)
+  : mUUID(uuid)
+{
+}
+
+TelemetrySessionData::~TelemetrySessionData()
+{
+}
+
+NS_IMETHODIMP
+TelemetrySessionData::GetUuid(nsACString &uuid)
+{
+  uuid = mUUID;
+  return NS_OK;
+}
+
+bool
+TelemetrySessionData::SampleReflector(EntryType *entry, JSContext *cx,
+                                      JSObject *snapshots)
+{
+  // Don't reflect histograms with no data associated with them.
+  if (entry->mData.sum() == 0) {
+    return true;
+  }
+
+  // This has the undesirable effect of creating a histogram for the
+  // current session with the given ID.  But there's no good way to
+  // compute the ranges and buckets from scratch.
+  Histogram *h = nsnull;
+  nsresult rv = GetHistogramByEnumId(Telemetry::ID(entry->GetKey()), &h);
+  if (NS_FAILED(rv)) {
+    return true;
+  }
+
+  JSObject *snapshot = JS_NewObject(cx, NULL, NULL, NULL);
+  if (!snapshot) {
+    return false;
+  }
+  JS::AutoObjectRooter root(cx, snapshot);
+  switch (ReflectHistogramAndSamples(cx, snapshot, h, entry->mData)) {
+  case REFLECT_OK:
+    return JS_DefineProperty(cx, snapshots,
+                             h->histogram_name().c_str(),
+                             OBJECT_TO_JSVAL(snapshot), NULL, NULL,
+                             JSPROP_ENUMERATE);
+  case REFLECT_CORRUPT:
+    // Just ignore this one.
+    return true;
+  case REFLECT_FAILURE:
+    return false;
+  default:
+    MOZ_NOT_REACHED("unhandled reflection status");
+    return false;
+  }
+}
+
+NS_IMETHODIMP
+TelemetrySessionData::GetSnapshots(JSContext *cx, jsval *ret)
+{
+  JSObject *snapshots = JS_NewObject(cx, NULL, NULL, NULL);
+  if (!snapshots) {
+    return NS_ERROR_FAILURE;
+  }
+  JS::AutoObjectRooter root(cx, snapshots);
+
+  if (!mSampleSetMap.ReflectHashtable(SampleReflector, cx, snapshots)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  *ret = OBJECT_TO_JSVAL(snapshots);
+  return NS_OK;
+}
+
+bool
+TelemetrySessionData::DeserializeHistogramData(Pickle &pickle, void **iter)
+{
+  uint32_t count = 0;
+  if (!pickle.ReadUInt32(iter, &count)) {
+    return false;
+  }
+
+  for (size_t i = 0; i < count; ++i) {
+    int stored_length;
+    const char *name;
+    if (!pickle.ReadData(iter, &name, &stored_length)) {
+      return false;
+    }
+
+    Telemetry::ID id;
+    nsresult rv = TelemetryImpl::GetHistogramEnumId(name, &id);
+    if (NS_FAILED(rv)) {
+      // We serialized a non-static histogram or we serialized a
+      // histogram that is no longer defined in TelemetryHistograms.h.
+      // Just drop its data on the floor.  If we can't deserialize the
+      // data, though, we're in trouble.
+      Histogram::SampleSet ss;
+      if (!ss.Deserialize(iter, pickle)) {
+        return false;
+      }
+    } else {
+      EntryType *entry = mSampleSetMap.GetEntry(id);
+      if (!entry) {
+        entry = mSampleSetMap.PutEntry(id);
+        if (NS_UNLIKELY(!entry)) {
+          return false;
+        }
+        if (!entry->mData.Deserialize(iter, pickle)) {
+          return false;
+        }
+      }
+    }
+  }
+
+  return true;
+}
+
+nsresult
+TelemetrySessionData::LoadFromDisk(nsIFile *file, TelemetrySessionData **ptr)
+{
+  *ptr = nsnull;
+  nsresult rv;
+
+  AutoFDClose fd;
+  rv = file->OpenNSPRFileDesc(PR_RDONLY, 0, &fd.rwget());
+  if (NS_FAILED(rv)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // If there's not even enough data to read the header for the pickle,
+  // don't bother.  Conveniently, this handles the error case as well.
+  int32_t size = PR_Available(fd);
+  if (size < static_cast<int32_t>(sizeof(Pickle::Header))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsAutoArrayPtr<char> data(new char[size]);
+  int32_t amount = PR_Read(fd, data, size);
+  if (amount != size) {
+    return NS_ERROR_FAILURE;
+  }
+
+  Pickle pickle(data, size);
+  void *iter = NULL;
+
+  // Make sure that how much data the pickle thinks it has corresponds
+  // with how much data we actually read.
+  const Pickle::Header *header = pickle.headerT<Pickle::Header>();
+  if (header->payload_size != static_cast<uint32_t>(amount) - sizeof(*header)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  unsigned int storedVersion;
+  if (!(pickle.ReadUInt32(&iter, &storedVersion)
+        && storedVersion == sVersion)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  const char *uuid;
+  int uuidLength;
+  if (!pickle.ReadData(&iter, &uuid, &uuidLength)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsAutoPtr<TelemetrySessionData> sessionData(new TelemetrySessionData(uuid));
+  if (!sessionData->DeserializeHistogramData(pickle, &iter)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  *ptr = sessionData.forget();
+  return NS_OK;
+}
+
+bool
+TelemetrySessionData::SerializeHistogramData(Pickle &pickle)
+{
+  StatisticsRecorder::Histograms hs;
+  StatisticsRecorder::GetHistograms(&hs);
+
+  if (!pickle.WriteUInt32(hs.size())) {
+    return false;
+  }
+
+  for (StatisticsRecorder::Histograms::const_iterator it = hs.begin();
+       it != hs.end();
+       ++it) {
+    const Histogram *h = *it;
+    const char *name = h->histogram_name().c_str();
+
+    // We don't check IsEmpty(h) here.  We discard no-data histograms on
+    // read-in, instead.  It's easier to write out the number of
+    // histograms required that way.  (The pickle interface doesn't make
+    // it easy to go back and overwrite previous data.)
+
+    Histogram::SampleSet ss;
+    h->SnapshotSample(&ss);
+
+    if (!(pickle.WriteData(name, strlen(name)+1)
+          && ss.Serialize(&pickle))) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+nsresult
+TelemetrySessionData::SaveToDisk(nsIFile *file, const nsACString &uuid)
+{
+  nsresult rv;
+
+  AutoFDClose fd;
+  rv = file->OpenNSPRFileDesc(PR_WRONLY | PR_CREATE_FILE | PR_TRUNCATE, 0600, &fd.rwget());
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  Pickle pickle;
+  if (!pickle.WriteUInt32(sVersion)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Include the trailing NULL for the UUID to make reading easier.
+  const char *data;
+  size_t length = uuid.GetData(&data);
+  if (!(pickle.WriteData(data, length+1)
+        && SerializeHistogramData(pickle))) {
+    return NS_ERROR_FAILURE;
+  }
+
+  int32_t amount = PR_Write(fd, static_cast<const char*>(pickle.data()),
+                            pickle.size());
+  if (amount != pickle.size()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+class SaveHistogramEvent : public nsRunnable
+{
+public:
+  SaveHistogramEvent(nsIFile *file, const nsACString &uuid,
+                     nsITelemetrySaveSessionDataCallback *callback)
+    : mFile(file), mUUID(uuid), mCallback(callback)
+  {}
+
+  NS_IMETHOD Run()
+  {
+    nsresult rv = TelemetrySessionData::SaveToDisk(mFile, mUUID);
+    mCallback->Handle(!!NS_SUCCEEDED(rv));
+    return rv;
+  }
+
+private:
+  nsCOMPtr<nsIFile> mFile;
+  nsCString mUUID;
+  nsCOMPtr<nsITelemetrySaveSessionDataCallback> mCallback;
+};
+
+NS_IMETHODIMP
+TelemetryImpl::SaveHistograms(nsIFile *file, const nsACString &uuid,
+                              nsITelemetrySaveSessionDataCallback *callback,
+                              bool isSynchronous)
+{
+  nsCOMPtr<nsIRunnable> event = new SaveHistogramEvent(file, uuid, callback);
+  if (isSynchronous) {
+    return event ? event->Run() : NS_ERROR_FAILURE;
+  } else {
+    return NS_DispatchToCurrentThread(event);
+  }
+}
+
+class LoadHistogramEvent : public nsRunnable
+{
+public:
+  LoadHistogramEvent(nsIFile *file,
+                     nsITelemetryLoadSessionDataCallback *callback)
+    : mFile(file), mCallback(callback)
+  {}
+
+  NS_IMETHOD Run()
+  {
+    TelemetrySessionData *sessionData = nsnull;
+    nsresult rv = TelemetrySessionData::LoadFromDisk(mFile, &sessionData);
+    if (NS_FAILED(rv)) {
+      mCallback->Handle(nsnull);
+    } else {
+      nsCOMPtr<nsITelemetrySessionData> data(sessionData);
+      mCallback->Handle(data);
+    }
+    return rv;
+  }
+
+private:
+  nsCOMPtr<nsIFile> mFile;
+  nsCOMPtr<nsITelemetryLoadSessionDataCallback> mCallback;
+};
+
+NS_IMETHODIMP
+TelemetryImpl::LoadHistograms(nsIFile *file,
+                              nsITelemetryLoadSessionDataCallback *callback,
+                              bool isSynchronous)
+{
+  nsCOMPtr<nsIRunnable> event = new LoadHistogramEvent(file, callback);
+  if (isSynchronous) {
+    return event ? event->Run() : NS_ERROR_FAILURE;
+  } else {
+    return NS_DispatchToCurrentThread(event);
+  }
+}
+
 NS_IMETHODIMP
 TelemetryImpl::GetCanRecord(bool *ret) {
   *ret = mCanRecord;

toolkit/components/telemetry/nsITelemetry.idl

@@ -6,7 +6,37 @@
 #include "nsISupports.idl"
 #include "nsIFile.idl"
 
-[scriptable, uuid(de54f594-4c20-4968-a27a-83b38ff952b9)]
+[scriptable, uuid(02719ffb-1a87-46cd-b8d3-5583f3267b32)]
+interface nsITelemetrySessionData : nsISupports
+{
+  /**
+   * The UUID of our previous session.
+   */
+  readonly attribute ACString uuid;
+
+  /**
+   * An object containing a snapshot from all registered histograms that had
+   * data recorded in the previous session.
+   * { name1: data1, name2: data2, .... }
+   * where the individual dataN are as nsITelemetry.histogramSnapshots.
+   */
+  [implicit_jscontext]
+  readonly attribute jsval snapshots;
+};
+
+[scriptable, function, uuid(aff36c9d-7e4c-41ab-a9b6-53773bbca0cd)]
+interface nsITelemetryLoadSessionDataCallback : nsISupports
+{
+  void handle(in nsITelemetrySessionData data);
+};
+
+[scriptable, function, uuid(40065f26-afd2-4417-93de-c1de9adb1548)]
+interface nsITelemetrySaveSessionDataCallback : nsISupports
+{
+  void handle(in bool success);
+};
+
+[scriptable, uuid(f23a2c8d-9286-42e9-ab1b-ed287eeade6d)]
 interface nsITelemetry : nsISupports
 {
   /**
@@ -118,6 +148,33 @@ interface nsITelemetry : nsISupports
   [implicit_jscontext]
   jsval getHistogramById(in ACString id);
 
+  /**
+   * Save persistent histograms to the given file.
+   *
+   * @param file - filename for saving
+   * @param uuid - UUID of this session
+   * @param callback - function to be caled when file writing is complete
+   */
+  void saveHistograms(in nsIFile file, in ACString uuid,
+                      in nsITelemetrySaveSessionDataCallback callback,
+                      in bool isSynchronous);
+
+  /* Reconstruct an nsITelemetryDataSession object containing histogram
+   * information from the given file; the file must have been produced
+   * via saveHistograms.
+   *
+   * This method does not modify the histogram information being
+   * collected in the current session.
+   *
+   * The reconstructed object is then passed to the given callback.
+   *
+   * @param file - the file to load histogram information from
+   * @param callback - function to process histogram information
+   */
+  void loadHistograms(in nsIFile file,
+                      in nsITelemetryLoadSessionDataCallback callback,
+                      in bool isSynchronous);
+
   /**
    * Set this to false to disable gathering of telemetry statistics.
    */

toolkit/components/telemetry/tests/unit/test_nsITelemetry.js

@@ -286,6 +286,39 @@ function generateUUID() {
   return str.substring(1, str.length - 1);
 }
 
+// Check that we do sane things when saving to disk.
+function test_loadSave()
+{
+  let dirService = Cc["@mozilla.org/file/directory_service;1"]
+                    .getService(Ci.nsIProperties);
+  let tmpDir = dirService.get("TmpD", Ci.nsILocalFile);
+  let tmpFile = tmpDir.clone();
+  tmpFile.append("saved-histograms.dat");
+  if (tmpFile.exists()) {
+    tmpFile.remove(true);
+  }
+
+  let saveFinished = false;
+  let loadFinished = false;
+  let uuid = generateUUID();
+  let loadCallback = function(data) {
+    do_check_true(data != null);
+    do_check_eq(uuid, data.uuid);
+    loadFinished = true;
+    do_test_finished();
+  };
+  let saveCallback = function(success) {
+    do_check_true(success);
+    Telemetry.loadHistograms(tmpFile, loadCallback, false);
+    saveFinished = true;
+  };
+  do_test_pending();
+  Telemetry.saveHistograms(tmpFile, uuid, saveCallback, false);
+  do_register_cleanup(function () do_check_true(saveFinished));
+  do_register_cleanup(function () do_check_true(loadFinished));
+  do_register_cleanup(function () tmpFile.remove(true));
+}
+
 function run_test()
 {
   let kinds = [Telemetry.HISTOGRAM_EXPONENTIAL, Telemetry.HISTOGRAM_LINEAR]
@@ -309,4 +342,5 @@ function run_test()
   test_getSlowSQL();
   test_privateMode();
   test_addons();
+  test_loadSave();
 }