MediaMetrics: Add stack allocated Item
Enable byte string submit for low overhead.
Add tests.
Test: atest mediametrics_tests
Bug: 138583596
Change-Id: Idce65fd270e8ad45ba754a660734368416c8d1b5
diff --git a/media/libmediametrics/include/MediaAnalyticsItem.h b/media/libmediametrics/include/MediaAnalyticsItem.h
index 5558211..bff7c9b 100644
--- a/media/libmediametrics/include/MediaAnalyticsItem.h
+++ b/media/libmediametrics/include/MediaAnalyticsItem.h
@@ -36,50 +36,346 @@
class Parcel;
/*
- * Media Metrics
- * Byte String format for communication of MediaAnalyticsItem.
+ * MediaMetrics Item
*
- * .... begin of item
- * .... begin of header
- * (uint32) length: including the length field itself
- * (uint32) header length, including header_length and length fields.
- * (uint16) version: 0
- * (uint16) key length, including zero termination
- * (int8)+ key string, including 0 termination
+ * Byte string format.
+ *
+ * For Java
+ * int64 corresponds to long
+ * int32, uint32 corresponds to int
+ * uint16 corresponds to char
+ * uint8, int8 corresponds to byte
+ *
+ * Hence uint8 and uint32 values are limited to INT8_MAX and INT32_MAX.
+ *
+ * Physical layout of integers and doubles within the MediaMetrics byte string
+ * is in Native / host order, which is nearly always little endian.
+ *
+ * -- begin of item
+ * -- begin of header
+ * (uint32) item size: including the item size field
+ * (uint32) header size, including the item size and header size fields.
+ * (uint16) version: exactly 0
+ * (uint16) key size, that is key strlen + 1 for zero termination.
+ * (int8)+ key string which is 0 terminated
* (int32) pid
* (int32) uid
* (int64) timestamp
- * .... end of header
- * .... begin body
- * (uint32) properties
- * #properties of the following:
- * (uint16) property_length, including property_length field itself
+ * -- end of header
+ * -- begin body
+ * (uint32) number of properties
+ * -- repeat for number of properties
+ * (uint16) property size, including property size field itself
* (uint8) type of property
* (int8)+ key string, including 0 termination
- * based on type of property (above), one of:
+ * based on type of property (given above), one of:
* (int32)
* (int64)
* (double)
* (int8)+ for cstring, including 0 termination
* (int64, int64) for rate
- * .... end body
- * .... end of item
+ * -- end body
+ * -- end of item
*/
+namespace mediametrics {
+
+// Type must match MediaMetrics.java
+enum Type {
+ kTypeNone = 0,
+ kTypeInt32 = 1,
+ kTypeInt64 = 2,
+ kTypeDouble = 3,
+ kTypeCString = 4,
+ kTypeRate = 5,
+};
+
+template<size_t N>
+static inline bool startsWith(const std::string &s, const char (&comp)[N]) {
+ return !strncmp(s.c_str(), comp, N-1);
+}
+
+/**
+ * Media Metrics BaseItem
+ *
+ * A base class which contains utility static functions to write to a byte stream
+ * and access the Media Metrics service.
+ */
+
+class BaseItem {
+ friend class MediaMetricsDeathNotifier; // for dropInstance
+ // enabled 1, disabled 0
+public:
+ // are we collecting analytics data
+ static bool isEnabled();
+
+protected:
+ static constexpr const char * const EnabledProperty = "media.metrics.enabled";
+ static constexpr const char * const EnabledPropertyPersist = "persist.media.metrics.enabled";
+ static const int EnabledProperty_default = 1;
+
+ // let's reuse a binder connection
+ static sp<IMediaAnalyticsService> sAnalyticsService;
+ static sp<IMediaAnalyticsService> getInstance();
+ static void dropInstance();
+ static bool submitBuffer(const char *buffer, size_t len);
+
+ static status_t writeToByteString(
+ const char *name, int32_t value, char **bufferpptr, char *bufferptrmax);
+ static status_t writeToByteString(
+ const char *name, int64_t value, char **bufferpptr, char *bufferptrmax);
+ static status_t writeToByteString(
+ const char *name, double value, char **bufferpptr, char *bufferptrmax);
+ static status_t writeToByteString(
+ const char *name, const std::pair<int64_t, int64_t> &value,
+ char **bufferpptr, char *bufferptrmax);
+ static status_t writeToByteString(
+ const char *name, char * const &value, char **bufferpptr, char *bufferptrmax);
+ static status_t writeToByteString(
+ const char *name, const char * const &value, char **bufferpptr, char *bufferptrmax);
+ struct none_t {}; // for kTypeNone
+ static status_t writeToByteString(
+ const char *name, const none_t &, char **bufferpptr, char *bufferptrmax);
+
+ template<typename T>
+ static status_t sizeOfByteString(const char *name, const T& value) {
+ return 2 + 1 + strlen(name) + 1 + sizeof(value);
+ }
+ template<> // static
+ status_t sizeOfByteString(const char *name, char * const &value) {
+ return 2 + 1 + strlen(name) + 1 + strlen(value) + 1;
+ }
+ template<> // static
+ status_t sizeOfByteString(const char *name, const char * const &value) {
+ return 2 + 1 + strlen(name) + 1 + strlen(value) + 1;
+ }
+ template<> // static
+ status_t sizeOfByteString(const char *name, const none_t &) {
+ return 2 + 1 + strlen(name) + 1;
+ }
+};
+
+/**
+ * Media Metrics BufferedItem
+ *
+ * A base class which represents a put-only Media Metrics item, storing
+ * the Media Metrics data in a buffer with begin and end pointers.
+ *
+ * If a property key is entered twice, it will be stored in the buffer twice,
+ * and (implementation defined) the last value for that key will be used
+ * by the Media Metrics service.
+ *
+ * For realloc, a baseRealloc pointer must be passed in either explicitly
+ * or implicitly in the constructor. This will be updated with the value used on realloc.
+ */
+class BufferedItem : public BaseItem {
+public:
+ static inline constexpr uint16_t kVersion = 0;
+
+ virtual ~BufferedItem() = default;
+ BufferedItem(const BufferedItem&) = delete;
+ BufferedItem& operator=(const BufferedItem&) = delete;
+
+ BufferedItem(const std::string key, char *begin, char *end)
+ : BufferedItem(key.c_str(), begin, end) { }
+
+ BufferedItem(const char *key, char *begin, char *end)
+ : BufferedItem(key, begin, end, nullptr) { }
+
+ BufferedItem(const char *key, char **begin, char *end)
+ : BufferedItem(key, *begin, end, begin) { }
+
+ BufferedItem(const char *key, char *begin, char *end, char **baseRealloc)
+ : mBegin(begin)
+ , mEnd(end)
+ , mBaseRealloc(baseRealloc)
+ {
+ init(key);
+ }
+
+ template<typename T>
+ BufferedItem &set(const char *key, const T& value) {
+ reallocFor(sizeOfByteString(key, value));
+ if (mStatus == NO_ERROR) {
+ mStatus = BaseItem::writeToByteString(key, value, &mBptr, mEnd);
+ ++mPropCount;
+ }
+ return *this;
+ }
+
+ template<typename T>
+ BufferedItem &set(const std::string& key, const T& value) {
+ return set(key.c_str(), value);
+ }
+
+ BufferedItem &setPid(pid_t pid) {
+ if (mStatus == NO_ERROR) {
+ copyTo(mBegin + mHeaderLen - 16, (int32_t)pid);
+ }
+ return *this;
+ }
+
+ BufferedItem &setUid(uid_t uid) {
+ if (mStatus == NO_ERROR) {
+ copyTo(mBegin + mHeaderLen - 12, (int32_t)uid);
+ }
+ return *this;
+ }
+
+ BufferedItem &setTimestamp(nsecs_t timestamp) {
+ if (mStatus == NO_ERROR) {
+ copyTo(mBegin + mHeaderLen - 8, (int64_t)timestamp);
+ }
+ return *this;
+ }
+
+ bool record() {
+ return updateHeader()
+ && BaseItem::submitBuffer(getBuffer(), getLength());
+ }
+
+ bool isValid () const {
+ return mStatus == NO_ERROR;
+ }
+
+ char *getBuffer() const { return mBegin; }
+ size_t getLength() const { return mBptr - mBegin; }
+ size_t getRemaining() const { return mEnd - mBptr; }
+ size_t getCapacity() const { return mEnd - mBegin; }
+
+ bool updateHeader() {
+ if (mStatus != NO_ERROR) return false;
+ copyTo(mBegin + 0, (uint32_t)getLength());
+ copyTo(mBegin + 4, (uint32_t)mHeaderLen);
+ copyTo(mBegin + mHeaderLen, (uint32_t)mPropCount);
+ return true;
+ }
+
+protected:
+ BufferedItem() = default;
+
+ void reallocFor(size_t required) {
+ if (mStatus != NO_ERROR) return;
+ const size_t remaining = getRemaining();
+ if (required <= remaining) return;
+ if (mBaseRealloc == nullptr) {
+ mStatus = NO_MEMORY;
+ return;
+ }
+
+ const size_t current = getLength();
+ size_t minimum = current + required;
+ if (minimum > SSIZE_MAX >> 1) {
+ mStatus = NO_MEMORY;
+ return;
+ }
+ minimum <<= 1;
+ void *newptr = realloc(*mBaseRealloc, minimum);
+ if (newptr == nullptr) {
+ mStatus = NO_MEMORY;
+ return;
+ }
+ if (newptr != *mBaseRealloc) {
+ // ALOGD("base changed! current:%zu new size %zu", current, minimum);
+ if (*mBaseRealloc == nullptr) {
+ memcpy(newptr, mBegin, current);
+ }
+ mBegin = (char *)newptr;
+ *mBaseRealloc = mBegin;
+ mEnd = mBegin + minimum;
+ mBptr = mBegin + current;
+ } else {
+ // ALOGD("base kept! current:%zu new size %zu", current, minimum);
+ mEnd = mBegin + minimum;
+ }
+ }
+ template<typename T>
+ void copyTo(char *ptr, const T& value) {
+ memcpy(ptr, &value, sizeof(value));
+ }
+
+ void init(const char *key) {
+ mBptr = mBegin;
+ const size_t keylen = strlen(key) + 1;
+ mHeaderLen = 4 + 4 + 2 + 2 + keylen + 4 + 4 + 8;
+ reallocFor(mHeaderLen);
+ if (mStatus != NO_ERROR) return;
+ mBptr = mBegin + mHeaderLen + 4; // this includes propcount.
+
+ if (mEnd < mBptr || keylen > UINT16_MAX) {
+ mStatus = NO_MEMORY;
+ mBptr = mEnd;
+ return;
+ }
+ copyTo(mBegin + 8, kVersion);
+ copyTo(mBegin + 10, (uint16_t)keylen);
+ strcpy(mBegin + 12, key);
+
+ // initialize some parameters (that could be overridden)
+ setPid(-1);
+ setUid(-1);
+ setTimestamp(0);
+ }
+
+ char *mBegin = nullptr;
+ char *mEnd = nullptr;
+ char **mBaseRealloc = nullptr; // set to an address if realloc should be done.
+ // upon return, that pointer is updated with
+ // whatever needs to be freed.
+ char *mBptr = nullptr;
+ status_t mStatus = NO_ERROR;
+ uint32_t mPropCount = 0;
+ uint32_t mHeaderLen = 0;
+};
+
+/**
+ * MediaMetrics Item is a stack allocated media analytics item used for
+ * fast logging. It falls over to a malloc if needed.
+ *
+ * This is templated with a buffer size to allocate on the stack.
+ */
+template <size_t N = 4096>
+class Item : public BufferedItem {
+public:
+ explicit Item(const std::string key) : Item(key.c_str()) { }
+
+ // Since this class will not be defined before the base class, we initialize variables
+ // in our own order.
+ explicit Item(const char *key) {
+ mBegin = mBuffer;
+ mEnd = mBuffer + N;
+ mBaseRealloc = &mReallocPtr;
+ init(key);
+ }
+
+ ~Item() override {
+ if (mReallocPtr != nullptr) { // do the check before calling free to avoid overhead.
+ free(mReallocPtr);
+ }
+ }
+
+private:
+ char *mReallocPtr = nullptr; // set non-null by base class if realloc happened.
+ char mBuffer[N];
+};
+
+} // mediametrics
+
/**
* Media Metrics MediaAnalyticsItem
*
* A mutable item representing an event or record that will be
- * logged with the Media Metrics service.
+ * logged with the Media Metrics service. For client logging, one should
+ * use the mediametrics::Item.
*
+ * The MediaAnalyticsItem is designed for the service as it has getters.
*/
-
-class MediaAnalyticsItem {
+class MediaAnalyticsItem : public mediametrics::BaseItem {
friend class MediaMetricsJNI; // TODO: remove this access
- friend class MediaMetricsDeathNotifier; // for dropInstance
public:
+ // TODO: remove this duplicate definition when frameworks base is updated.
enum Type {
kTypeNone = 0,
kTypeInt32 = 1,
@@ -281,28 +577,12 @@
status_t writeToByteString(char **bufferptr, size_t *length) const;
status_t readFromByteString(const char *bufferptr, size_t length);
- static status_t writeToByteString(
- const char *name, int32_t value, char **bufferpptr, char *bufferptrmax);
- static status_t writeToByteString(
- const char *name, int64_t value, char **bufferpptr, char *bufferptrmax);
- static status_t writeToByteString(
- const char *name, double value, char **bufferpptr, char *bufferptrmax);
- static status_t writeToByteString(
- const char *name, const std::pair<int64_t, int64_t> &value, char **bufferpptr, char *bufferptrmax);
- static status_t writeToByteString(
- const char *name, char * const &value, char **bufferpptr, char *bufferptrmax);
- struct none_t {}; // for kTypeNone
- static status_t writeToByteString(
- const char *name, const none_t &, char **bufferpptr, char *bufferptrmax);
std::string toString() const;
std::string toString(int version) const;
const char *toCString();
const char *toCString(int version);
- // are we collecting analytics data
- static bool isEnabled();
-
protected:
// merge fields from arg into this
@@ -316,15 +596,7 @@
int32_t writeToParcel0(Parcel *) const;
int32_t readFromParcel0(const Parcel&);
- // enabled 1, disabled 0
- static constexpr const char * const EnabledProperty = "media.metrics.enabled";
- static constexpr const char * const EnabledPropertyPersist = "persist.media.metrics.enabled";
- static const int EnabledProperty_default = 1;
- // let's reuse a binder connection
- static sp<IMediaAnalyticsService> sAnalyticsService;
- static sp<IMediaAnalyticsService> getInstance();
- static void dropInstance();
// checks equality even with nullptr.
static bool stringEquals(const char *a, const char *b) {
@@ -435,7 +707,29 @@
}
bool isNamed(const char *name) const {
- return strcmp(name, mName) == 0;
+ return stringEquals(name, mName);
+ }
+
+ template <typename T> void visit(T f) const {
+ switch (mType) {
+ case MediaAnalyticsItem::kTypeInt32:
+ f(u.int32Value);
+ return;
+ case MediaAnalyticsItem::kTypeInt64:
+ f(u.int64Value);
+ return;
+ case MediaAnalyticsItem::kTypeDouble:
+ f(u.doubleValue);
+ return;
+ case MediaAnalyticsItem::kTypeRate:
+ f(u.rate);
+ return;
+ case MediaAnalyticsItem::kTypeCString:
+ f(u.CStringValue);
+ return;
+ default:
+ return;
+ }
}
template <typename T> bool get(T *value) const = delete;