move BlobCache over (unmodified) to libEGL

Test: compiled & run
Bug: vndk-stable
Change-Id: I7e816d80456bd1fa890b10b8d5f255deea49b841
diff --git a/opengl/libs/EGL/BlobCache.cpp b/opengl/libs/EGL/BlobCache.cpp
new file mode 100644
index 0000000..b0fdd44
--- /dev/null
+++ b/opengl/libs/EGL/BlobCache.cpp
@@ -0,0 +1,376 @@
+/*
+ ** Copyright 2011, 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 "BlobCache"
+//#define LOG_NDEBUG 0
+
+#include <utils/BlobCache.h>
+#include <utils/Timers.h>
+
+#include <inttypes.h>
+
+#include <cutils/properties.h>
+
+namespace android {
+
+// BlobCache::Header::mMagicNumber value
+static const uint32_t blobCacheMagic = ('_' << 24) + ('B' << 16) + ('b' << 8) + '$';
+
+// BlobCache::Header::mBlobCacheVersion value
+static const uint32_t blobCacheVersion = 3;
+
+// BlobCache::Header::mDeviceVersion value
+static const uint32_t blobCacheDeviceVersion = 1;
+
+BlobCache::BlobCache(size_t maxKeySize, size_t maxValueSize, size_t maxTotalSize):
+        mMaxKeySize(maxKeySize),
+        mMaxValueSize(maxValueSize),
+        mMaxTotalSize(maxTotalSize),
+        mTotalSize(0) {
+    nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
+#ifdef _WIN32
+    srand(now);
+#else
+    mRandState[0] = (now >> 0) & 0xFFFF;
+    mRandState[1] = (now >> 16) & 0xFFFF;
+    mRandState[2] = (now >> 32) & 0xFFFF;
+#endif
+    ALOGV("initializing random seed using %lld", (unsigned long long)now);
+}
+
+void BlobCache::set(const void* key, size_t keySize, const void* value,
+        size_t valueSize) {
+    if (mMaxKeySize < keySize) {
+        ALOGV("set: not caching because the key is too large: %zu (limit: %zu)",
+                keySize, mMaxKeySize);
+        return;
+    }
+    if (mMaxValueSize < valueSize) {
+        ALOGV("set: not caching because the value is too large: %zu (limit: %zu)",
+                valueSize, mMaxValueSize);
+        return;
+    }
+    if (mMaxTotalSize < keySize + valueSize) {
+        ALOGV("set: not caching because the combined key/value size is too "
+                "large: %zu (limit: %zu)", keySize + valueSize, mMaxTotalSize);
+        return;
+    }
+    if (keySize == 0) {
+        ALOGW("set: not caching because keySize is 0");
+        return;
+    }
+    if (valueSize <= 0) {
+        ALOGW("set: not caching because valueSize is 0");
+        return;
+    }
+
+    sp<Blob> dummyKey(new Blob(key, keySize, false));
+    CacheEntry dummyEntry(dummyKey, NULL);
+
+    while (true) {
+        ssize_t index = mCacheEntries.indexOf(dummyEntry);
+        if (index < 0) {
+            // Create a new cache entry.
+            sp<Blob> keyBlob(new Blob(key, keySize, true));
+            sp<Blob> valueBlob(new Blob(value, valueSize, true));
+            size_t newTotalSize = mTotalSize + keySize + valueSize;
+            if (mMaxTotalSize < newTotalSize) {
+                if (isCleanable()) {
+                    // Clean the cache and try again.
+                    clean();
+                    continue;
+                } else {
+                    ALOGV("set: not caching new key/value pair because the "
+                            "total cache size limit would be exceeded: %zu "
+                            "(limit: %zu)",
+                            keySize + valueSize, mMaxTotalSize);
+                    break;
+                }
+            }
+            mCacheEntries.add(CacheEntry(keyBlob, valueBlob));
+            mTotalSize = newTotalSize;
+            ALOGV("set: created new cache entry with %zu byte key and %zu byte value",
+                    keySize, valueSize);
+        } else {
+            // Update the existing cache entry.
+            sp<Blob> valueBlob(new Blob(value, valueSize, true));
+            sp<Blob> oldValueBlob(mCacheEntries[index].getValue());
+            size_t newTotalSize = mTotalSize + valueSize - oldValueBlob->getSize();
+            if (mMaxTotalSize < newTotalSize) {
+                if (isCleanable()) {
+                    // Clean the cache and try again.
+                    clean();
+                    continue;
+                } else {
+                    ALOGV("set: not caching new value because the total cache "
+                            "size limit would be exceeded: %zu (limit: %zu)",
+                            keySize + valueSize, mMaxTotalSize);
+                    break;
+                }
+            }
+            mCacheEntries.editItemAt(index).setValue(valueBlob);
+            mTotalSize = newTotalSize;
+            ALOGV("set: updated existing cache entry with %zu byte key and %zu byte "
+                    "value", keySize, valueSize);
+        }
+        break;
+    }
+}
+
+size_t BlobCache::get(const void* key, size_t keySize, void* value,
+        size_t valueSize) {
+    if (mMaxKeySize < keySize) {
+        ALOGV("get: not searching because the key is too large: %zu (limit %zu)",
+                keySize, mMaxKeySize);
+        return 0;
+    }
+    sp<Blob> dummyKey(new Blob(key, keySize, false));
+    CacheEntry dummyEntry(dummyKey, NULL);
+    ssize_t index = mCacheEntries.indexOf(dummyEntry);
+    if (index < 0) {
+        ALOGV("get: no cache entry found for key of size %zu", keySize);
+        return 0;
+    }
+
+    // The key was found. Return the value if the caller's buffer is large
+    // enough.
+    sp<Blob> valueBlob(mCacheEntries[index].getValue());
+    size_t valueBlobSize = valueBlob->getSize();
+    if (valueBlobSize <= valueSize) {
+        ALOGV("get: copying %zu bytes to caller's buffer", valueBlobSize);
+        memcpy(value, valueBlob->getData(), valueBlobSize);
+    } else {
+        ALOGV("get: caller's buffer is too small for value: %zu (needs %zu)",
+                valueSize, valueBlobSize);
+    }
+    return valueBlobSize;
+}
+
+static inline size_t align4(size_t size) {
+    return (size + 3) & ~3;
+}
+
+size_t BlobCache::getFlattenedSize() const {
+    size_t size = align4(sizeof(Header) + PROPERTY_VALUE_MAX);
+    for (size_t i = 0; i < mCacheEntries.size(); i++) {
+        const CacheEntry& e(mCacheEntries[i]);
+        sp<Blob> keyBlob = e.getKey();
+        sp<Blob> valueBlob = e.getValue();
+        size += align4(sizeof(EntryHeader) + keyBlob->getSize() +
+                       valueBlob->getSize());
+    }
+    return size;
+}
+
+status_t BlobCache::flatten(void* buffer, size_t size) const {
+    // Write the cache header
+    if (size < sizeof(Header)) {
+        ALOGE("flatten: not enough room for cache header");
+        return BAD_VALUE;
+    }
+    Header* header = reinterpret_cast<Header*>(buffer);
+    header->mMagicNumber = blobCacheMagic;
+    header->mBlobCacheVersion = blobCacheVersion;
+    header->mDeviceVersion = blobCacheDeviceVersion;
+    header->mNumEntries = mCacheEntries.size();
+    char buildId[PROPERTY_VALUE_MAX];
+    header->mBuildIdLength = property_get("ro.build.id", buildId, "");
+    memcpy(header->mBuildId, buildId, header->mBuildIdLength);
+
+    // Write cache entries
+    uint8_t* byteBuffer = reinterpret_cast<uint8_t*>(buffer);
+    off_t byteOffset = align4(sizeof(Header) + header->mBuildIdLength);
+    for (size_t i = 0; i < mCacheEntries.size(); i++) {
+        const CacheEntry& e(mCacheEntries[i]);
+        sp<Blob> keyBlob = e.getKey();
+        sp<Blob> valueBlob = e.getValue();
+        size_t keySize = keyBlob->getSize();
+        size_t valueSize = valueBlob->getSize();
+
+        size_t entrySize = sizeof(EntryHeader) + keySize + valueSize;
+        size_t totalSize = align4(entrySize);
+        if (byteOffset + totalSize > size) {
+            ALOGE("flatten: not enough room for cache entries");
+            return BAD_VALUE;
+        }
+
+        EntryHeader* eheader = reinterpret_cast<EntryHeader*>(
+            &byteBuffer[byteOffset]);
+        eheader->mKeySize = keySize;
+        eheader->mValueSize = valueSize;
+
+        memcpy(eheader->mData, keyBlob->getData(), keySize);
+        memcpy(eheader->mData + keySize, valueBlob->getData(), valueSize);
+
+        if (totalSize > entrySize) {
+            // We have padding bytes. Those will get written to storage, and contribute to the CRC,
+            // so make sure we zero-them to have reproducible results.
+            memset(eheader->mData + keySize + valueSize, 0, totalSize - entrySize);
+        }
+
+        byteOffset += totalSize;
+    }
+
+    return OK;
+}
+
+status_t BlobCache::unflatten(void const* buffer, size_t size) {
+    // All errors should result in the BlobCache being in an empty state.
+    mCacheEntries.clear();
+
+    // Read the cache header
+    if (size < sizeof(Header)) {
+        ALOGE("unflatten: not enough room for cache header");
+        return BAD_VALUE;
+    }
+    const Header* header = reinterpret_cast<const Header*>(buffer);
+    if (header->mMagicNumber != blobCacheMagic) {
+        ALOGE("unflatten: bad magic number: %" PRIu32, header->mMagicNumber);
+        return BAD_VALUE;
+    }
+    char buildId[PROPERTY_VALUE_MAX];
+    int len = property_get("ro.build.id", buildId, "");
+    if (header->mBlobCacheVersion != blobCacheVersion ||
+            header->mDeviceVersion != blobCacheDeviceVersion ||
+            len != header->mBuildIdLength ||
+            strncmp(buildId, header->mBuildId, len)) {
+        // We treat version mismatches as an empty cache.
+        return OK;
+    }
+
+    // Read cache entries
+    const uint8_t* byteBuffer = reinterpret_cast<const uint8_t*>(buffer);
+    off_t byteOffset = align4(sizeof(Header) + header->mBuildIdLength);
+    size_t numEntries = header->mNumEntries;
+    for (size_t i = 0; i < numEntries; i++) {
+        if (byteOffset + sizeof(EntryHeader) > size) {
+            mCacheEntries.clear();
+            ALOGE("unflatten: not enough room for cache entry headers");
+            return BAD_VALUE;
+        }
+
+        const EntryHeader* eheader = reinterpret_cast<const EntryHeader*>(
+                &byteBuffer[byteOffset]);
+        size_t keySize = eheader->mKeySize;
+        size_t valueSize = eheader->mValueSize;
+        size_t entrySize = sizeof(EntryHeader) + keySize + valueSize;
+
+        size_t totalSize = align4(entrySize);
+        if (byteOffset + totalSize > size) {
+            mCacheEntries.clear();
+            ALOGE("unflatten: not enough room for cache entry headers");
+            return BAD_VALUE;
+        }
+
+        const uint8_t* data = eheader->mData;
+        set(data, keySize, data + keySize, valueSize);
+
+        byteOffset += totalSize;
+    }
+
+    return OK;
+}
+
+long int BlobCache::blob_random() {
+#ifdef _WIN32
+    return rand();
+#else
+    return nrand48(mRandState);
+#endif
+}
+
+void BlobCache::clean() {
+    // Remove a random cache entry until the total cache size gets below half
+    // the maximum total cache size.
+    while (mTotalSize > mMaxTotalSize / 2) {
+        size_t i = size_t(blob_random() % (mCacheEntries.size()));
+        const CacheEntry& entry(mCacheEntries[i]);
+        mTotalSize -= entry.getKey()->getSize() + entry.getValue()->getSize();
+        mCacheEntries.removeAt(i);
+    }
+}
+
+bool BlobCache::isCleanable() const {
+    return mTotalSize > mMaxTotalSize / 2;
+}
+
+BlobCache::Blob::Blob(const void* data, size_t size, bool copyData):
+        mData(copyData ? malloc(size) : data),
+        mSize(size),
+        mOwnsData(copyData) {
+    if (data != NULL && copyData) {
+        memcpy(const_cast<void*>(mData), data, size);
+    }
+}
+
+BlobCache::Blob::~Blob() {
+    if (mOwnsData) {
+        free(const_cast<void*>(mData));
+    }
+}
+
+bool BlobCache::Blob::operator<(const Blob& rhs) const {
+    if (mSize == rhs.mSize) {
+        return memcmp(mData, rhs.mData, mSize) < 0;
+    } else {
+        return mSize < rhs.mSize;
+    }
+}
+
+const void* BlobCache::Blob::getData() const {
+    return mData;
+}
+
+size_t BlobCache::Blob::getSize() const {
+    return mSize;
+}
+
+BlobCache::CacheEntry::CacheEntry() {
+}
+
+BlobCache::CacheEntry::CacheEntry(const sp<Blob>& key, const sp<Blob>& value):
+        mKey(key),
+        mValue(value) {
+}
+
+BlobCache::CacheEntry::CacheEntry(const CacheEntry& ce):
+        mKey(ce.mKey),
+        mValue(ce.mValue) {
+}
+
+bool BlobCache::CacheEntry::operator<(const CacheEntry& rhs) const {
+    return *mKey < *rhs.mKey;
+}
+
+const BlobCache::CacheEntry& BlobCache::CacheEntry::operator=(const CacheEntry& rhs) {
+    mKey = rhs.mKey;
+    mValue = rhs.mValue;
+    return *this;
+}
+
+sp<BlobCache::Blob> BlobCache::CacheEntry::getKey() const {
+    return mKey;
+}
+
+sp<BlobCache::Blob> BlobCache::CacheEntry::getValue() const {
+    return mValue;
+}
+
+void BlobCache::CacheEntry::setValue(const sp<Blob>& value) {
+    mValue = value;
+}
+
+} // namespace android
diff --git a/opengl/libs/EGL/BlobCache.h b/opengl/libs/EGL/BlobCache.h
new file mode 100644
index 0000000..27a81e3
--- /dev/null
+++ b/opengl/libs/EGL/BlobCache.h
@@ -0,0 +1,247 @@
+/*
+ ** Copyright 2011, 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 ANDROID_BLOB_CACHE_H
+#define ANDROID_BLOB_CACHE_H
+
+#include <stddef.h>
+
+#include <utils/RefBase.h>
+#include <utils/SortedVector.h>
+
+namespace android {
+
+// A BlobCache is an in-memory cache for binary key/value pairs.  A BlobCache
+// does NOT provide any thread-safety guarantees.
+//
+// The cache contents can be serialized to an in-memory buffer or mmap'd file
+// and then reloaded in a subsequent execution of the program.  This
+// serialization is non-portable and the data should only be used by the device
+// that generated it.
+class BlobCache : public RefBase {
+
+public:
+
+    // Create an empty blob cache. The blob cache will cache key/value pairs
+    // with key and value sizes less than or equal to maxKeySize and
+    // maxValueSize, respectively. The total combined size of ALL cache entries
+    // (key sizes plus value sizes) will not exceed maxTotalSize.
+    BlobCache(size_t maxKeySize, size_t maxValueSize, size_t maxTotalSize);
+
+    // set inserts a new binary value into the cache and associates it with the
+    // given binary key.  If the key or value are too large for the cache then
+    // the cache remains unchanged.  This includes the case where a different
+    // value was previously associated with the given key - the old value will
+    // remain in the cache.  If the given key and value are small enough to be
+    // put in the cache (based on the maxKeySize, maxValueSize, and maxTotalSize
+    // values specified to the BlobCache constructor), then the key/value pair
+    // will be in the cache after set returns.  Note, however, that a subsequent
+    // call to set may evict old key/value pairs from the cache.
+    //
+    // Preconditions:
+    //   key != NULL
+    //   0 < keySize
+    //   value != NULL
+    //   0 < valueSize
+    void set(const void* key, size_t keySize, const void* value,
+            size_t valueSize);
+
+    // get retrieves from the cache the binary value associated with a given
+    // binary key.  If the key is present in the cache then the length of the
+    // binary value associated with that key is returned.  If the value argument
+    // is non-NULL and the size of the cached value is less than valueSize bytes
+    // then the cached value is copied into the buffer pointed to by the value
+    // argument.  If the key is not present in the cache then 0 is returned and
+    // the buffer pointed to by the value argument is not modified.
+    //
+    // Note that when calling get multiple times with the same key, the later
+    // calls may fail, returning 0, even if earlier calls succeeded.  The return
+    // value must be checked for each call.
+    //
+    // Preconditions:
+    //   key != NULL
+    //   0 < keySize
+    //   0 <= valueSize
+    size_t get(const void* key, size_t keySize, void* value, size_t valueSize);
+
+
+    // getFlattenedSize returns the number of bytes needed to store the entire
+    // serialized cache.
+    size_t getFlattenedSize() const;
+
+    // flatten serializes the current contents of the cache into the memory
+    // pointed to by 'buffer'.  The serialized cache contents can later be
+    // loaded into a BlobCache object using the unflatten method.  The contents
+    // of the BlobCache object will not be modified.
+    //
+    // Preconditions:
+    //   size >= this.getFlattenedSize()
+    status_t flatten(void* buffer, size_t size) const;
+
+    // unflatten replaces the contents of the cache with the serialized cache
+    // contents in the memory pointed to by 'buffer'.  The previous contents of
+    // the BlobCache will be evicted from the cache.  If an error occurs while
+    // unflattening the serialized cache contents then the BlobCache will be
+    // left in an empty state.
+    //
+    status_t unflatten(void const* buffer, size_t size);
+
+private:
+    // Copying is disallowed.
+    BlobCache(const BlobCache&);
+    void operator=(const BlobCache&);
+
+    // A random function helper to get around MinGW not having nrand48()
+    long int blob_random();
+
+    // clean evicts a randomly chosen set of entries from the cache such that
+    // the total size of all remaining entries is less than mMaxTotalSize/2.
+    void clean();
+
+    // isCleanable returns true if the cache is full enough for the clean method
+    // to have some effect, and false otherwise.
+    bool isCleanable() const;
+
+    // A Blob is an immutable sized unstructured data blob.
+    class Blob : public RefBase {
+    public:
+        Blob(const void* data, size_t size, bool copyData);
+        ~Blob();
+
+        bool operator<(const Blob& rhs) const;
+
+        const void* getData() const;
+        size_t getSize() const;
+
+    private:
+        // Copying is not allowed.
+        Blob(const Blob&);
+        void operator=(const Blob&);
+
+        // mData points to the buffer containing the blob data.
+        const void* mData;
+
+        // mSize is the size of the blob data in bytes.
+        size_t mSize;
+
+        // mOwnsData indicates whether or not this Blob object should free the
+        // memory pointed to by mData when the Blob gets destructed.
+        bool mOwnsData;
+    };
+
+    // A CacheEntry is a single key/value pair in the cache.
+    class CacheEntry {
+    public:
+        CacheEntry();
+        CacheEntry(const sp<Blob>& key, const sp<Blob>& value);
+        CacheEntry(const CacheEntry& ce);
+
+        bool operator<(const CacheEntry& rhs) const;
+        const CacheEntry& operator=(const CacheEntry&);
+
+        sp<Blob> getKey() const;
+        sp<Blob> getValue() const;
+
+        void setValue(const sp<Blob>& value);
+
+    private:
+
+        // mKey is the key that identifies the cache entry.
+        sp<Blob> mKey;
+
+        // mValue is the cached data associated with the key.
+        sp<Blob> mValue;
+    };
+
+    // A Header is the header for the entire BlobCache serialization format. No
+    // need to make this portable, so we simply write the struct out.
+    struct Header {
+        // mMagicNumber is the magic number that identifies the data as
+        // serialized BlobCache contents.  It must always contain 'Blb$'.
+        uint32_t mMagicNumber;
+
+        // mBlobCacheVersion is the serialization format version.
+        uint32_t mBlobCacheVersion;
+
+        // mDeviceVersion is the device-specific version of the cache.  This can
+        // be used to invalidate the cache.
+        uint32_t mDeviceVersion;
+
+        // mNumEntries is number of cache entries following the header in the
+        // data.
+        size_t mNumEntries;
+
+        // mBuildId is the build id of the device when the cache was created.
+        // When an update to the build happens (via an OTA or other update) this
+        // is used to invalidate the cache.
+        int mBuildIdLength;
+        char mBuildId[];
+    };
+
+    // An EntryHeader is the header for a serialized cache entry.  No need to
+    // make this portable, so we simply write the struct out.  Each EntryHeader
+    // is followed imediately by the key data and then the value data.
+    //
+    // The beginning of each serialized EntryHeader is 4-byte aligned, so the
+    // number of bytes that a serialized cache entry will occupy is:
+    //
+    //   ((sizeof(EntryHeader) + keySize + valueSize) + 3) & ~3
+    //
+    struct EntryHeader {
+        // mKeySize is the size of the entry key in bytes.
+        size_t mKeySize;
+
+        // mValueSize is the size of the entry value in bytes.
+        size_t mValueSize;
+
+        // mData contains both the key and value data for the cache entry.  The
+        // key comes first followed immediately by the value.
+        uint8_t mData[];
+    };
+
+    // mMaxKeySize is the maximum key size that will be cached. Calls to
+    // BlobCache::set with a keySize parameter larger than mMaxKeySize will
+    // simply not add the key/value pair to the cache.
+    const size_t mMaxKeySize;
+
+    // mMaxValueSize is the maximum value size that will be cached. Calls to
+    // BlobCache::set with a valueSize parameter larger than mMaxValueSize will
+    // simply not add the key/value pair to the cache.
+    const size_t mMaxValueSize;
+
+    // mMaxTotalSize is the maximum size that all cache entries can occupy. This
+    // includes space for both keys and values. When a call to BlobCache::set
+    // would otherwise cause this limit to be exceeded, either the key/value
+    // pair passed to BlobCache::set will not be cached or other cache entries
+    // will be evicted from the cache to make room for the new entry.
+    const size_t mMaxTotalSize;
+
+    // mTotalSize is the total combined size of all keys and values currently in
+    // the cache.
+    size_t mTotalSize;
+
+    // mRandState is the pseudo-random number generator state. It is passed to
+    // nrand48 to generate random numbers when needed.
+    unsigned short mRandState[3];
+
+    // mCacheEntries stores all the cache entries that are resident in memory.
+    // Cache entries are added to it by the 'set' method.
+    SortedVector<CacheEntry> mCacheEntries;
+};
+
+}
+
+#endif // ANDROID_BLOB_CACHE_H