UID mapping to provide app name and version.

The UID map is updated by StatsCompanionService, which listens to broadcast
updates indicating that an app was updated/installed or removed. Also,
the entire map is updated when statsd first connects to the companion
service. Also, there is a way for metrics producers to subscribe to
updates, so that they can know when an app was upgraded.

Test: Created new unit-test for mapping and manually tested for install
and remove. Did not manually test the app upgrade.

Change-Id: I6676ae5c93b75c72d9badabb36aa9c40006db07d
diff --git a/cmds/statsd/src/UidMap.h b/cmds/statsd/src/UidMap.h
new file mode 100644
index 0000000..1481010
--- /dev/null
+++ b/cmds/statsd/src/UidMap.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef STATSD_UIDMAP_H
+#define STATSD_UIDMAP_H
+
+#include "frameworks/base/cmds/statsd/src/stats_log.pb.h"
+#include "PackageInfoListener.h"
+
+#include <binder/IResultReceiver.h>
+#include <binder/IShellCallback.h>
+#include <log/logprint.h>
+#include <mutex>
+#include <string>
+#include <stdio.h>
+#include <set>
+#include <unordered_map>
+#include <utils/RefBase.h>
+
+using namespace std;
+
+namespace android {
+namespace os {
+namespace statsd {
+
+struct AppData {
+    const string packageName;
+    int versionCode;
+
+    AppData(const string& a, const int v) : packageName(a), versionCode(v) {};
+};
+
+// UidMap keeps track of what the corresponding app name (APK name) and version code for every uid
+// at any given moment. This map must be updated by StatsCompanionService.
+class UidMap : public virtual android::RefBase  {
+public:
+    /*
+     * All three inputs must be the same size, and the jth element in each array refers to the same
+     * tuple, ie. uid[j] corresponds to packageName[j] with versionCode[j].
+     */
+    void updateMap(const vector<int32_t>& uid, const vector<int32_t>& versionCode,
+                   const vector<String16>& packageName);
+
+    // Returns true if the given uid contains the specified app (eg. com.google.android.gms).
+    bool hasApp(int uid, const string& packageName) const;
+
+    int getAppVersion(int uid, const string& packageName) const;
+
+    void updateApp(const String16& packageName, const int32_t& uid, const int32_t& versionCode);
+    void removeApp(const String16& packageName, const int32_t& uid);
+
+    // Helper for debugging contents of this uid map. Can be triggered with:
+    // adb shell cmd stats print-uid-map
+    void printUidMap(FILE* out);
+
+    // Commands for indicating to the map that a producer should be notified if an app is updated.
+    // This allows the metric producer to distinguish when the same uid or app represents a
+    // different version of an app.
+    void addListener(sp<PackageInfoListener> producer);
+    // Remove the listener from the set of metric producers that subscribe to updates.
+    void removeListener(sp<PackageInfoListener> producer);
+
+    // Grabs the current output contents and then clears it.
+    UidMapping getAndClearOutput();
+
+private:
+    // TODO: Use shared_mutex for improved read-locking if a library can be found in Android.
+    mutable mutex mMutex;
+
+    std::unordered_multimap<int, AppData> mMap;
+
+    // We prepare the output proto as apps are updated, so that we can grab the current output.
+    UidMapping mOutput;
+
+    // Metric producers that should be notified if there's an upgrade in any app.
+    set<sp<PackageInfoListener>> mSubscribers;
+};
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
+
+#endif //STATSD_UIDMAP_H
+