diff --git a/media/libmediametrics/MediaMetricsItem.cpp b/media/libmediametrics/MediaMetricsItem.cpp
new file mode 100644
index 0000000..98158d2
--- /dev/null
+++ b/media/libmediametrics/MediaMetricsItem.cpp
@@ -0,0 +1,1035 @@
+/*
+ * 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.
+ */
+
+#define LOG_TAG "mediametrics::Item"
+
+#include <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+
+#include <mutex>
+#include <set>
+
+#include <binder/Parcel.h>
+#include <utils/Errors.h>
+#include <utils/Log.h>
+#include <utils/SortedVector.h>
+#include <utils/threads.h>
+
+#include <binder/IServiceManager.h>
+#include <media/IMediaMetricsService.h>
+#include <media/MediaMetricsItem.h>
+#include <private/android_filesystem_config.h>
+
+// Max per-property string size before truncation in toString().
+// Do not make too large, as this is used for dumpsys purposes.
+static constexpr size_t kMaxPropertyStringSize = 4096;
+
+namespace android::mediametrics {
+
+#define DEBUG_SERVICEACCESS     0
+#define DEBUG_API               0
+#define DEBUG_ALLOCATIONS       0
+
+// after this many failed attempts, we stop trying [from this process] and just say that
+// the service is off.
+#define SVC_TRIES               2
+
+mediametrics::Item* mediametrics::Item::convert(mediametrics_handle_t handle) {
+    mediametrics::Item *item = (android::mediametrics::Item *) handle;
+    return item;
+}
+
+mediametrics_handle_t mediametrics::Item::convert(mediametrics::Item *item ) {
+    mediametrics_handle_t handle = (mediametrics_handle_t) item;
+    return handle;
+}
+
+mediametrics::Item::~Item() {
+    if (DEBUG_ALLOCATIONS) {
+        ALOGD("Destroy  mediametrics::Item @ %p", this);
+    }
+    clear();
+}
+
+void mediametrics::Item::clear() {
+
+    // clean allocated storage from key
+    mKey.clear();
+
+    // clean attributes
+    // contents of the attributes
+    for (size_t i = 0 ; i < mPropCount; i++ ) {
+        mProps[i].clear();
+    }
+    // the attribute records themselves
+    if (mProps != NULL) {
+        free(mProps);
+        mProps = NULL;
+    }
+    mPropSize = 0;
+    mPropCount = 0;
+
+    return;
+}
+
+// make a deep copy of myself
+mediametrics::Item *mediametrics::Item::dup() {
+    mediametrics::Item *dst = new mediametrics::Item(this->mKey);
+
+    if (dst != NULL) {
+        // key as part of constructor
+        dst->mPid = this->mPid;
+        dst->mUid = this->mUid;
+        dst->mPkgName = this->mPkgName;
+        dst->mPkgVersionCode = this->mPkgVersionCode;
+        dst->mTimestamp = this->mTimestamp;
+
+        // properties aka attributes
+        dst->growProps(this->mPropCount);
+        for(size_t i=0;i<mPropCount;i++) {
+            dst->mProps[i] = this->mProps[i];
+        }
+        dst->mPropCount = this->mPropCount;
+    }
+
+    return dst;
+}
+
+mediametrics::Item &mediametrics::Item::setTimestamp(nsecs_t ts) {
+    mTimestamp = ts;
+    return *this;
+}
+
+nsecs_t mediametrics::Item::getTimestamp() const {
+    return mTimestamp;
+}
+
+mediametrics::Item &mediametrics::Item::setPid(pid_t pid) {
+    mPid = pid;
+    return *this;
+}
+
+pid_t mediametrics::Item::getPid() const {
+    return mPid;
+}
+
+mediametrics::Item &mediametrics::Item::setUid(uid_t uid) {
+    mUid = uid;
+    return *this;
+}
+
+uid_t mediametrics::Item::getUid() const {
+    return mUid;
+}
+
+mediametrics::Item &mediametrics::Item::setPkgName(const std::string &pkgName) {
+    mPkgName = pkgName;
+    return *this;
+}
+
+mediametrics::Item &mediametrics::Item::setPkgVersionCode(int64_t pkgVersionCode) {
+    mPkgVersionCode = pkgVersionCode;
+    return *this;
+}
+
+int64_t mediametrics::Item::getPkgVersionCode() const {
+    return mPkgVersionCode;
+}
+
+
+// find the proper entry in the list
+size_t mediametrics::Item::findPropIndex(const char *name) const
+{
+    size_t i = 0;
+    for (; i < mPropCount; i++) {
+        if (mProps[i].isNamed(name)) break;
+    }
+    return i;
+}
+
+mediametrics::Item::Prop *mediametrics::Item::findProp(const char *name) const {
+    const size_t i = findPropIndex(name);
+    if (i < mPropCount) {
+        return &mProps[i];
+    }
+    return nullptr;
+}
+
+// consider this "find-or-allocate".
+// caller validates type and uses clearPropValue() accordingly
+mediametrics::Item::Prop *mediametrics::Item::allocateProp(const char *name) {
+    const size_t i = findPropIndex(name);
+    if (i < mPropCount) {
+        return &mProps[i]; // already have it, return
+    }
+
+    Prop *prop = allocateProp(); // get a new prop
+    if (prop == nullptr) return nullptr;
+    prop->setName(name);
+    return prop;
+}
+
+mediametrics::Item::Prop *mediametrics::Item::allocateProp() {
+    if (mPropCount == mPropSize && growProps() == false) {
+        ALOGE("%s: failed allocation for new properties", __func__);
+        return nullptr;
+    }
+    return &mProps[mPropCount++];
+}
+
+// used within the summarizers; return whether property existed
+bool mediametrics::Item::removeProp(const char *name) {
+    const size_t i = findPropIndex(name);
+    if (i < mPropCount) {
+        mProps[i].clear();
+        if (i != mPropCount-1) {
+            // in the middle, bring last one down to fill gap
+            mProps[i].swap(mProps[mPropCount-1]);
+        }
+        mPropCount--;
+        return true;
+    }
+    return false;
+}
+
+// remove indicated keys and their values
+// return value is # keys removed
+size_t mediametrics::Item::filter(size_t n, const char *attrs[]) {
+    size_t zapped = 0;
+    for (size_t i = 0; i < n; ++i) {
+        const char *name = attrs[i];
+        size_t j = findPropIndex(name);
+        if (j >= mPropCount) {
+            // not there
+            continue;
+        } else if (j + 1 == mPropCount) {
+            // last one, shorten
+            zapped++;
+            mProps[j].clear();
+            mPropCount--;
+        } else {
+            // in the middle, bring last one down and shorten
+            zapped++;
+            mProps[j].clear();
+            mProps[j] = mProps[mPropCount-1];
+            mPropCount--;
+        }
+    }
+    return zapped;
+}
+
+// remove any keys NOT in the provided list
+// return value is # keys removed
+size_t mediametrics::Item::filterNot(size_t n, const char *attrs[]) {
+    std::set<std::string> check(attrs, attrs + n);
+    size_t zapped = 0;
+    for (size_t j = 0; j < mPropCount;) {
+        if (check.find(mProps[j].getName()) != check.end()) {
+            ++j;
+            continue;
+        }
+        if (j + 1 == mPropCount) {
+            // last one, shorten
+            zapped++;
+            mProps[j].clear();
+            mPropCount--;
+            break;
+        } else {
+            // in the middle, bring last one down and shorten
+            zapped++;
+            mProps[j].clear();
+            mProps[j] = mProps[mPropCount-1];
+            mPropCount--;
+        }
+    }
+    return zapped;
+}
+
+bool mediametrics::Item::growProps(int increment)
+{
+    if (increment <= 0) {
+        increment = kGrowProps;
+    }
+    int nsize = mPropSize + increment;
+    Prop *ni = (Prop *)realloc(mProps, sizeof(Prop) * nsize);
+
+    if (ni != NULL) {
+        for (int i = mPropSize; i < nsize; i++) {
+            new (&ni[i]) Prop(); // placement new
+        }
+        mProps = ni;
+        mPropSize = nsize;
+        return true;
+    } else {
+        ALOGW("mediametrics::Item::growProps fails");
+        return false;
+    }
+}
+
+// Parcel / serialize things for binder calls
+//
+
+status_t mediametrics::Item::readFromParcel(const Parcel& data) {
+    int32_t version;
+    status_t status = data.readInt32(&version);
+    if (status != NO_ERROR) return status;
+
+    switch (version) {
+    case 0:
+      return readFromParcel0(data);
+    default:
+      ALOGE("%s: unsupported parcel version: %d", __func__, version);
+      return INVALID_OPERATION;
+    }
+}
+
+status_t mediametrics::Item::readFromParcel0(const Parcel& data) {
+    const char *s = data.readCString();
+    mKey = s == nullptr ? "" : s;
+    int32_t pid, uid;
+    status_t status = data.readInt32(&pid) ?: data.readInt32(&uid);
+    if (status != NO_ERROR) return status;
+    mPid = (pid_t)pid;
+    mUid = (uid_t)uid;
+    s = data.readCString();
+    mPkgName = s == nullptr ? "" : s;
+    int32_t count;
+    int64_t version, timestamp;
+    status = data.readInt64(&version) ?: data.readInt64(&timestamp) ?: data.readInt32(&count);
+    if (status != NO_ERROR) return status;
+    if (count < 0) return BAD_VALUE;
+    mPkgVersionCode = version;
+    mTimestamp = timestamp;
+    for (int i = 0; i < count ; i++) {
+        Prop *prop = allocateProp();
+        status_t status = prop->readFromParcel(data);
+        if (status != NO_ERROR) return status;
+    }
+    return NO_ERROR;
+}
+
+status_t mediametrics::Item::writeToParcel(Parcel *data) const {
+    if (data == nullptr) return BAD_VALUE;
+
+    const int32_t version = 0;
+    status_t status = data->writeInt32(version);
+    if (status != NO_ERROR) return status;
+
+    switch (version) {
+    case 0:
+      return writeToParcel0(data);
+    default:
+      ALOGE("%s: unsupported parcel version: %d", __func__, version);
+      return INVALID_OPERATION;
+    }
+}
+
+status_t mediametrics::Item::writeToParcel0(Parcel *data) const {
+    status_t status =
+        data->writeCString(mKey.c_str())
+        ?: data->writeInt32(mPid)
+        ?: data->writeInt32(mUid)
+        ?: data->writeCString(mPkgName.c_str())
+        ?: data->writeInt64(mPkgVersionCode)
+        ?: data->writeInt64(mTimestamp);
+    if (status != NO_ERROR) return status;
+
+    data->writeInt32((int32_t)mPropCount);
+    for (size_t i = 0 ; i < mPropCount; ++i) {
+        status = mProps[i].writeToParcel(data);
+        if (status != NO_ERROR) return status;
+    }
+    return NO_ERROR;
+}
+
+const char *mediametrics::Item::toCString() {
+   return toCString(PROTO_LAST);
+}
+
+const char * mediametrics::Item::toCString(int version) {
+    std::string val = toString(version);
+    return strdup(val.c_str());
+}
+
+std::string mediametrics::Item::toString() const {
+   return toString(PROTO_LAST);
+}
+
+std::string mediametrics::Item::toString(int version) const {
+    std::string result;
+    char buffer[kMaxPropertyStringSize];
+
+    snprintf(buffer, sizeof(buffer), "[%d:%s:%d:%d:%lld:%s:%zu:",
+            version, mKey.c_str(), mPid, mUid, (long long)mTimestamp,
+            mPkgName.c_str(), mPropCount);
+    result.append(buffer);
+    for (size_t i = 0 ; i < mPropCount; ++i) {
+        mProps[i].toString(buffer, sizeof(buffer));
+        result.append(buffer);
+    }
+    result.append("]");
+    return result;
+}
+
+// for the lazy, we offer methods that finds the service and
+// calls the appropriate daemon
+bool mediametrics::Item::selfrecord() {
+    ALOGD_IF(DEBUG_API, "%s: delivering %s", __func__, this->toString().c_str());
+    sp<IMediaMetricsService> svc = getInstance();
+    if (svc != NULL) {
+        status_t status = svc->submit(this);
+        if (status != NO_ERROR) {
+            ALOGW("%s: failed to record: %s", __func__, this->toString().c_str());
+            return false;
+        }
+        return true;
+    } else {
+        return false;
+    }
+}
+
+//static
+bool BaseItem::isEnabled() {
+    // completely skip logging from certain UIDs. We do this here
+    // to avoid the multi-second timeouts while we learn that
+    // sepolicy will not let us find the service.
+    // We do this only for a select set of UIDs
+    // The sepolicy protection is still in place, we just want a faster
+    // response from this specific, small set of uids.
+
+    // This is checked only once in the lifetime of the process.
+    const uid_t uid = getuid();
+    switch (uid) {
+    case AID_RADIO:     // telephony subsystem, RIL
+        return false;
+    }
+
+    int enabled = property_get_int32(Item::EnabledProperty, -1);
+    if (enabled == -1) {
+        enabled = property_get_int32(Item::EnabledPropertyPersist, -1);
+    }
+    if (enabled == -1) {
+        enabled = Item::EnabledProperty_default;
+    }
+    return enabled > 0;
+}
+
+// monitor health of our connection to the metrics service
+class MediaMetricsDeathNotifier : public IBinder::DeathRecipient {
+        virtual void binderDied(const wp<IBinder> &) {
+            ALOGW("Reacquire service connection on next request");
+            BaseItem::dropInstance();
+        }
+};
+
+static sp<MediaMetricsDeathNotifier> sNotifier;
+// static
+sp<IMediaMetricsService> BaseItem::sMediaMetricsService;
+static std::mutex sServiceMutex;
+static int sRemainingBindAttempts = SVC_TRIES;
+
+// static
+void BaseItem::dropInstance() {
+    std::lock_guard  _l(sServiceMutex);
+    sRemainingBindAttempts = SVC_TRIES;
+    sMediaMetricsService = nullptr;
+}
+
+// static
+bool BaseItem::submitBuffer(const char *buffer, size_t size) {
+/*
+    mediametrics::Item item;
+    status_t status = item.readFromByteString(buffer, size);
+    ALOGD("%s: status:%d, size:%zu, item:%s", __func__, status, size, item.toString().c_str());
+    return item.selfrecord();
+    */
+
+    ALOGD_IF(DEBUG_API, "%s: delivering %zu bytes", __func__, size);
+    sp<IMediaMetricsService> svc = getInstance();
+    if (svc != nullptr) {
+        const status_t status = svc->submitBuffer(buffer, size);
+        if (status != NO_ERROR) {
+            ALOGW("%s: failed(%d) to record: %zu bytes", __func__, status, size);
+            return false;
+        }
+        return true;
+    }
+    return false;
+}
+
+//static
+sp<IMediaMetricsService> BaseItem::getInstance() {
+    static const char *servicename = "media.metrics";
+    static const bool enabled = isEnabled(); // singleton initialized
+
+    if (enabled == false) {
+        ALOGD_IF(DEBUG_SERVICEACCESS, "disabled");
+        return nullptr;
+    }
+    std::lock_guard _l(sServiceMutex);
+    // think of remainingBindAttempts as telling us whether service == nullptr because
+    // (1) we haven't tried to initialize it yet
+    // (2) we've tried to initialize it, but failed.
+    if (sMediaMetricsService == nullptr && sRemainingBindAttempts > 0) {
+        const char *badness = "";
+        sp<IServiceManager> sm = defaultServiceManager();
+        if (sm != nullptr) {
+            sp<IBinder> binder = sm->getService(String16(servicename));
+            if (binder != nullptr) {
+                sMediaMetricsService = interface_cast<IMediaMetricsService>(binder);
+                sNotifier = new MediaMetricsDeathNotifier();
+                binder->linkToDeath(sNotifier);
+            } else {
+                badness = "did not find service";
+            }
+        } else {
+            badness = "No Service Manager access";
+        }
+        if (sMediaMetricsService == nullptr) {
+            if (sRemainingBindAttempts > 0) {
+                sRemainingBindAttempts--;
+            }
+            ALOGD_IF(DEBUG_SERVICEACCESS, "%s: unable to bind to service %s: %s",
+                    __func__, servicename, badness);
+        }
+    }
+    return sMediaMetricsService;
+}
+
+
+// merge the info from 'incoming' into this record.
+// we finish with a union of this+incoming and special handling for collisions
+bool mediametrics::Item::merge(mediametrics::Item *incoming) {
+
+    // if I don't have key or session id, take them from incoming
+    // 'this' should never be missing both of them...
+    if (mKey.empty()) {
+        mKey = incoming->mKey;
+    }
+
+    // for each attribute from 'incoming', resolve appropriately
+    int nattr = incoming->mPropCount;
+    for (int i = 0 ; i < nattr; i++ ) {
+        Prop *iprop = &incoming->mProps[i];
+        const char *p = iprop->mName;
+        size_t len = strlen(p);
+
+        // should ignore a zero length name...
+        if (len == 0) {
+            continue;
+        }
+
+        Prop *oprop = findProp(iprop->mName);
+
+        if (oprop == NULL) {
+            // no oprop, so we insert the new one
+            oprop = allocateProp(p);
+            if (oprop != NULL) {
+                *oprop = *iprop;
+            } else {
+                ALOGW("dropped property '%s'", iprop->mName);
+            }
+        } else {
+            *oprop = *iprop;
+        }
+    }
+
+    // not sure when we'd return false...
+    return true;
+}
+
+namespace {
+
+template <typename T>
+status_t insert(const T& val, char **bufferpptr, char *bufferptrmax)
+{
+    const size_t size = sizeof(val);
+    if (*bufferpptr + size > bufferptrmax) {
+        ALOGE("%s: buffer exceeded with size %zu", __func__, size);
+        return BAD_VALUE;
+    }
+    memcpy(*bufferpptr, &val, size);
+    *bufferpptr += size;
+    return NO_ERROR;
+}
+
+template <>
+status_t insert(const char * const& val, char **bufferpptr, char *bufferptrmax)
+{
+    const size_t size = strlen(val) + 1;
+    if (size > UINT16_MAX || *bufferpptr + size > bufferptrmax) {
+        ALOGE("%s: buffer exceeded with size %zu", __func__, size);
+        return BAD_VALUE;
+    }
+    memcpy(*bufferpptr, val, size);
+    *bufferpptr += size;
+    return NO_ERROR;
+}
+
+template <>
+ __unused
+status_t insert(char * const& val, char **bufferpptr, char *bufferptrmax)
+{
+    return insert((const char *)val, bufferpptr, bufferptrmax);
+}
+
+template <typename T>
+status_t extract(T *val, const char **bufferpptr, const char *bufferptrmax)
+{
+    const size_t size = sizeof(*val);
+    if (*bufferpptr + size > bufferptrmax) {
+        ALOGE("%s: buffer exceeded with size %zu", __func__, size);
+        return BAD_VALUE;
+    }
+    memcpy(val, *bufferpptr, size);
+    *bufferpptr += size;
+    return NO_ERROR;
+}
+
+template <>
+status_t extract(char **val, const char **bufferpptr, const char *bufferptrmax)
+{
+    const char *ptr = *bufferpptr;
+    while (*ptr != 0) {
+        if (ptr >= bufferptrmax) {
+            ALOGE("%s: buffer exceeded", __func__);
+            return BAD_VALUE;
+        }
+        ++ptr;
+    }
+    const size_t size = (ptr - *bufferpptr) + 1;
+    *val = (char *)malloc(size);
+    memcpy(*val, *bufferpptr, size);
+    *bufferpptr += size;
+    return NO_ERROR;
+}
+
+} // namespace
+
+status_t mediametrics::Item::writeToByteString(char **pbuffer, size_t *plength) const
+{
+    if (pbuffer == nullptr || plength == nullptr)
+        return BAD_VALUE;
+
+    // get size
+    const size_t keySizeZeroTerminated = strlen(mKey.c_str()) + 1;
+    if (keySizeZeroTerminated > UINT16_MAX) {
+        ALOGW("%s: key size %zu too large", __func__, keySizeZeroTerminated);
+        return INVALID_OPERATION;
+    }
+    const uint16_t version = 0;
+    const uint32_t header_size =
+        sizeof(uint32_t)      // total size
+        + sizeof(header_size) // header size
+        + sizeof(version)     // encoding version
+        + sizeof(uint16_t)    // key size
+        + keySizeZeroTerminated // key, zero terminated
+        + sizeof(int32_t)     // pid
+        + sizeof(int32_t)     // uid
+        + sizeof(int64_t)     // timestamp
+        ;
+
+    uint32_t size = header_size
+        + sizeof(uint32_t) // # properties
+        ;
+    for (size_t i = 0 ; i < mPropCount; ++i) {
+        const size_t propSize = mProps[i].getByteStringSize();
+        if (propSize > UINT16_MAX) {
+            ALOGW("%s: prop %zu size %zu too large", __func__, i, propSize);
+            return INVALID_OPERATION;
+        }
+        if (__builtin_add_overflow(size, propSize, &size)) {
+            ALOGW("%s: item size overflow at property %zu", __func__, i);
+            return INVALID_OPERATION;
+        }
+    }
+
+    // since we fill every byte in the buffer (there is no padding),
+    // malloc is used here instead of calloc.
+    char * const build = (char *)malloc(size);
+    if (build == nullptr) return NO_MEMORY;
+
+    char *filling = build;
+    char *buildmax = build + size;
+    if (insert((uint32_t)size, &filling, buildmax) != NO_ERROR
+            || insert(header_size, &filling, buildmax) != NO_ERROR
+            || insert(version, &filling, buildmax) != NO_ERROR
+            || insert((uint16_t)keySizeZeroTerminated, &filling, buildmax) != NO_ERROR
+            || insert(mKey.c_str(), &filling, buildmax) != NO_ERROR
+            || insert((int32_t)mPid, &filling, buildmax) != NO_ERROR
+            || insert((int32_t)mUid, &filling, buildmax) != NO_ERROR
+            || insert((int64_t)mTimestamp, &filling, buildmax) != NO_ERROR
+            || insert((uint32_t)mPropCount, &filling, buildmax) != NO_ERROR) {
+        ALOGE("%s:could not write header", __func__);  // shouldn't happen
+        free(build);
+        return INVALID_OPERATION;
+    }
+    for (size_t i = 0 ; i < mPropCount; ++i) {
+        if (mProps[i].writeToByteString(&filling, buildmax) != NO_ERROR) {
+            free(build);
+            // shouldn't happen
+            ALOGE("%s:could not write prop %zu of %zu", __func__, i, mPropCount);
+            return INVALID_OPERATION;
+        }
+    }
+
+    if (filling != buildmax) {
+        ALOGE("%s: problems populating; wrote=%d planned=%d",
+                __func__, (int)(filling - build), (int)size);
+        free(build);
+        return INVALID_OPERATION;
+    }
+    *pbuffer = build;
+    *plength = size;
+    return NO_ERROR;
+}
+
+status_t mediametrics::Item::readFromByteString(const char *bufferptr, size_t length)
+{
+    if (bufferptr == nullptr) return BAD_VALUE;
+
+    const char *read = bufferptr;
+    const char *readend = bufferptr + length;
+
+    uint32_t size;
+    uint32_t header_size;
+    uint16_t version;
+    uint16_t key_size;
+    char *key = nullptr;
+    int32_t pid;
+    int32_t uid;
+    int64_t timestamp;
+    uint32_t propCount;
+    if (extract(&size, &read, readend) != NO_ERROR
+            || extract(&header_size, &read, readend) != NO_ERROR
+            || extract(&version, &read, readend) != NO_ERROR
+            || extract(&key_size, &read, readend) != NO_ERROR
+            || extract(&key, &read, readend) != NO_ERROR
+            || extract(&pid, &read, readend) != NO_ERROR
+            || extract(&uid, &read, readend) != NO_ERROR
+            || extract(&timestamp, &read, readend) != NO_ERROR
+            || size > length
+            || strlen(key) + 1 != key_size
+            || header_size > size) {
+        free(key);
+        ALOGW("%s: invalid header", __func__);
+        return INVALID_OPERATION;
+    }
+    mKey = key;
+    free(key);
+    const size_t pos = read - bufferptr;
+    if (pos > header_size) {
+        ALOGW("%s: invalid header pos:%zu > header_size:%u",
+                __func__, pos, header_size);
+        return INVALID_OPERATION;
+    } else if (pos < header_size) {
+        ALOGW("%s: mismatched header pos:%zu < header_size:%u, advancing",
+                __func__, pos, header_size);
+        read += (header_size - pos);
+    }
+    if (extract(&propCount, &read, readend) != NO_ERROR) {
+        ALOGD("%s: cannot read prop count", __func__);
+        return INVALID_OPERATION;
+    }
+    mPid = pid;
+    mUid = uid;
+    mTimestamp = timestamp;
+    for (size_t i = 0; i < propCount; ++i) {
+        Prop *prop = allocateProp();
+        if (prop->readFromByteString(&read, readend) != NO_ERROR) {
+            ALOGW("%s: cannot read prop %zu", __func__, i);
+            return INVALID_OPERATION;
+        }
+    }
+    return NO_ERROR;
+}
+
+status_t mediametrics::Item::Prop::writeToParcel(Parcel *data) const
+{
+   switch (mType) {
+   case kTypeInt32:
+       return data->writeCString(mName)
+               ?: data->writeInt32(mType)
+               ?: data->writeInt32(u.int32Value);
+   case kTypeInt64:
+       return data->writeCString(mName)
+               ?: data->writeInt32(mType)
+               ?: data->writeInt64(u.int64Value);
+   case kTypeDouble:
+       return data->writeCString(mName)
+               ?: data->writeInt32(mType)
+               ?: data->writeDouble(u.doubleValue);
+   case kTypeRate:
+       return data->writeCString(mName)
+               ?: data->writeInt32(mType)
+               ?: data->writeInt64(u.rate.first)
+               ?: data->writeInt64(u.rate.second);
+   case kTypeCString:
+       return data->writeCString(mName)
+               ?: data->writeInt32(mType)
+               ?: data->writeCString(u.CStringValue);
+   default:
+       ALOGE("%s: found bad type: %d, name %s", __func__, mType, mName);
+       return BAD_VALUE;
+   }
+}
+
+status_t mediametrics::Item::Prop::readFromParcel(const Parcel& data)
+{
+    const char *key = data.readCString();
+    if (key == nullptr) return BAD_VALUE;
+    int32_t type;
+    status_t status = data.readInt32(&type);
+    if (status != NO_ERROR) return status;
+    switch (type) {
+    case kTypeInt32:
+        status = data.readInt32(&u.int32Value);
+        break;
+    case kTypeInt64:
+        status = data.readInt64(&u.int64Value);
+        break;
+    case kTypeDouble:
+        status = data.readDouble(&u.doubleValue);
+        break;
+    case kTypeCString: {
+        const char *s = data.readCString();
+        if (s == nullptr) return BAD_VALUE;
+        set(s);
+        break;
+        }
+    case kTypeRate: {
+        std::pair<int64_t, int64_t> rate;
+        status = data.readInt64(&rate.first)
+                ?: data.readInt64(&rate.second);
+        if (status == NO_ERROR) {
+            set(rate);
+        }
+        break;
+        }
+    default:
+        ALOGE("%s: reading bad item type: %d", __func__, mType);
+        return BAD_VALUE;
+    }
+    if (status == NO_ERROR) {
+        setName(key);
+        mType = (Type)type;
+    }
+    return status;
+}
+
+void mediametrics::Item::Prop::toString(char *buffer, size_t length) const
+{
+    switch (mType) {
+    case kTypeInt32:
+        snprintf(buffer, length, "%s=%d:", mName, u.int32Value);
+        break;
+    case mediametrics::Item::kTypeInt64:
+        snprintf(buffer, length, "%s=%lld:", mName, (long long)u.int64Value);
+        break;
+    case mediametrics::Item::kTypeDouble:
+        snprintf(buffer, length, "%s=%e:", mName, u.doubleValue);
+        break;
+    case mediametrics::Item::kTypeRate:
+        snprintf(buffer, length, "%s=%lld/%lld:",
+                mName, (long long)u.rate.first, (long long)u.rate.second);
+        break;
+    case mediametrics::Item::kTypeCString:
+        // TODO sanitize string for ':' '='
+        snprintf(buffer, length, "%s=%s:", mName, u.CStringValue);
+        break;
+    default:
+        ALOGE("%s: bad item type: %d for %s", __func__, mType, mName);
+        if (length > 0) buffer[0] = 0;
+        break;
+    }
+}
+
+size_t mediametrics::Item::Prop::getByteStringSize() const
+{
+    const size_t header =
+        sizeof(uint16_t)      // length
+        + sizeof(uint8_t)     // type
+        + strlen(mName) + 1;  // mName + 0 termination
+    size_t payload = 0;
+    switch (mType) {
+    case mediametrics::Item::kTypeInt32:
+        payload = sizeof(u.int32Value);
+        break;
+    case mediametrics::Item::kTypeInt64:
+        payload = sizeof(u.int64Value);
+        break;
+    case mediametrics::Item::kTypeDouble:
+        payload = sizeof(u.doubleValue);
+        break;
+    case mediametrics::Item::kTypeRate:
+        payload = sizeof(u.rate.first) + sizeof(u.rate.second);
+        break;
+    case mediametrics::Item::kTypeCString:
+        payload = strlen(u.CStringValue) + 1;
+        break;
+    default:
+        ALOGE("%s: found bad prop type: %d, name %s",
+                __func__, mType, mName); // no payload computed
+        break;
+    }
+    return header + payload;
+}
+
+
+// TODO: fold into a template later.
+status_t BaseItem::writeToByteString(
+        const char *name, int32_t value, char **bufferpptr, char *bufferptrmax)
+{
+    const size_t len = 2 + 1 + strlen(name) + 1 + sizeof(value);
+    if (len > UINT16_MAX) return BAD_VALUE;
+    return insert((uint16_t)len, bufferpptr, bufferptrmax)
+            ?: insert((uint8_t)kTypeInt32, bufferpptr, bufferptrmax)
+            ?: insert(name, bufferpptr, bufferptrmax)
+            ?: insert(value, bufferpptr, bufferptrmax);
+}
+
+status_t BaseItem::writeToByteString(
+        const char *name, int64_t value, char **bufferpptr, char *bufferptrmax)
+{
+    const size_t len = 2 + 1 + strlen(name) + 1 + sizeof(value);
+    if (len > UINT16_MAX) return BAD_VALUE;
+    return insert((uint16_t)len, bufferpptr, bufferptrmax)
+            ?: insert((uint8_t)kTypeInt64, bufferpptr, bufferptrmax)
+            ?: insert(name, bufferpptr, bufferptrmax)
+            ?: insert(value, bufferpptr, bufferptrmax);
+}
+
+status_t BaseItem::writeToByteString(
+        const char *name, double value, char **bufferpptr, char *bufferptrmax)
+{
+    const size_t len = 2 + 1 + strlen(name) + 1 + sizeof(value);
+    if (len > UINT16_MAX) return BAD_VALUE;
+    return insert((uint16_t)len, bufferpptr, bufferptrmax)
+            ?: insert((uint8_t)kTypeDouble, bufferpptr, bufferptrmax)
+            ?: insert(name, bufferpptr, bufferptrmax)
+            ?: insert(value, bufferpptr, bufferptrmax);
+}
+
+status_t BaseItem::writeToByteString(
+        const char *name, const std::pair<int64_t, int64_t> &value, char **bufferpptr, char *bufferptrmax)
+{
+    const size_t len = 2 + 1 + strlen(name) + 1 + 8 + 8;
+    if (len > UINT16_MAX) return BAD_VALUE;
+    return insert((uint16_t)len, bufferpptr, bufferptrmax)
+            ?: insert((uint8_t)kTypeRate, bufferpptr, bufferptrmax)
+            ?: insert(name, bufferpptr, bufferptrmax)
+            ?: insert(value.first, bufferpptr, bufferptrmax)
+            ?: insert(value.second, bufferpptr, bufferptrmax);
+}
+
+status_t BaseItem::writeToByteString(
+        const char *name, char * const &value, char **bufferpptr, char *bufferptrmax)
+{
+    return writeToByteString(name, (const char *)value, bufferpptr, bufferptrmax);
+}
+
+status_t BaseItem::writeToByteString(
+        const char *name, const char * const &value, char **bufferpptr, char *bufferptrmax)
+{
+    const size_t len = 2 + 1 + strlen(name) + 1 + strlen(value) + 1;
+    if (len > UINT16_MAX) return BAD_VALUE;
+    return insert((uint16_t)len, bufferpptr, bufferptrmax)
+            ?: insert((uint8_t)kTypeCString, bufferpptr, bufferptrmax)
+            ?: insert(name, bufferpptr, bufferptrmax)
+            ?: insert(value, bufferpptr, bufferptrmax);
+}
+
+
+status_t BaseItem::writeToByteString(
+        const char *name, const none_t &, char **bufferpptr, char *bufferptrmax)
+{
+    const size_t len = 2 + 1 + strlen(name) + 1;
+    if (len > UINT16_MAX) return BAD_VALUE;
+    return insert((uint16_t)len, bufferpptr, bufferptrmax)
+            ?: insert((uint8_t)kTypeCString, bufferpptr, bufferptrmax)
+            ?: insert(name, bufferpptr, bufferptrmax);
+}
+
+
+status_t mediametrics::Item::Prop::writeToByteString(
+        char **bufferpptr, char *bufferptrmax) const
+{
+    switch (mType) {
+    case kTypeInt32:
+        return BaseItem::writeToByteString(mName, u.int32Value, bufferpptr, bufferptrmax);
+    case kTypeInt64:
+        return BaseItem::writeToByteString(mName, u.int64Value, bufferpptr, bufferptrmax);
+    case kTypeDouble:
+        return BaseItem::writeToByteString(mName, u.doubleValue, bufferpptr, bufferptrmax);
+    case kTypeRate:
+        return BaseItem::writeToByteString(mName, u.rate, bufferpptr, bufferptrmax);
+    case kTypeCString:
+        return BaseItem::writeToByteString(mName, u.CStringValue, bufferpptr, bufferptrmax);
+    case kTypeNone:
+        return BaseItem::writeToByteString(mName, none_t{}, bufferpptr, bufferptrmax);
+    default:
+        ALOGE("%s: found bad prop type: %d, name %s",
+                __func__, mType, mName);  // no payload sent
+        return BAD_VALUE;
+    }
+}
+
+status_t mediametrics::Item::Prop::readFromByteString(
+        const char **bufferpptr, const char *bufferptrmax)
+{
+    uint16_t len;
+    char *name;
+    uint8_t type;
+    status_t status = extract(&len, bufferpptr, bufferptrmax)
+            ?: extract(&type, bufferpptr, bufferptrmax)
+            ?: extract(&name, bufferpptr, bufferptrmax);
+    if (status != NO_ERROR) return status;
+    if (mName != nullptr) {
+        free(mName);
+    }
+    mName = name;
+    if (mType == kTypeCString) {
+        free(u.CStringValue);
+        u.CStringValue = nullptr;
+    }
+    mType = (Type)type;
+    switch (mType) {
+    case kTypeInt32:
+        return extract(&u.int32Value, bufferpptr, bufferptrmax);
+    case kTypeInt64:
+        return extract(&u.int64Value, bufferpptr, bufferptrmax);
+    case kTypeDouble:
+        return extract(&u.doubleValue, bufferpptr, bufferptrmax);
+    case kTypeRate:
+        return extract(&u.rate.first, bufferpptr, bufferptrmax)
+                ?: extract(&u.rate.second, bufferpptr, bufferptrmax);
+    case kTypeCString:
+        status = extract(&u.CStringValue, bufferpptr, bufferptrmax);
+        if (status != NO_ERROR) mType = kTypeNone;
+        return status;
+    case kTypeNone:
+        return NO_ERROR;
+    default:
+        mType = kTypeNone;
+        ALOGE("%s: found bad prop type: %d, name %s",
+                __func__, mType, mName);  // no payload sent
+        return BAD_VALUE;
+    }
+}
+
+} // namespace android::mediametrics