Add ability to store and retrieve a list of MapBuffer

Summary:
Add ability to store and retrieve a list of MapBuffer as an entry of MapBuffer.

```
Example:

MapBuffer1
{
 key1: "test string",
 key2: MapBuffer2,
 key3: [MapBuffer3, MapBuffer4]
}
```

Changelog:
[General][Added] Add ability to store and retrieve a list of MapBuffer

Reviewed By: JoshuaGross

Differential Revision: D38460204

fbshipit-source-id: 3e721418be2dca6d5f15f665753844d6f531e31c

ReactAndroid/src/main/java/com/facebook/react/common/mapbuffer/MapBuffer.kt

@@ -126,6 +126,16 @@ interface MapBuffer : Iterable<MapBuffer.Entry> {
    */
   fun getMapBuffer(key: Int): MapBuffer
 
+  /**
+   * Provides parsed [List<MapBuffer>] value if the entry for given key exists with [DataType.MAP]
+   * type
+   * @param key key to lookup [List<MapBuffer>] value for
+   * @return value associated with the requested key
+   * @throws IllegalArgumentException if the key doesn't exist
+   * @throws IllegalStateException if the data type doesn't match
+   */
+  fun getMapBufferList(key: Int): List<MapBuffer>
+
   /** Iterable entry representing parsed MapBuffer values */
   interface Entry {
     /**

ReactAndroid/src/main/java/com/facebook/react/common/mapbuffer/ReadableMapBuffer.kt

@@ -137,6 +137,24 @@ class ReadableMapBuffer : MapBuffer {
     return ReadableMapBuffer(ByteBuffer.wrap(newBuffer))
   }
 
+  private fun readMapBufferListValue(position: Int): List<ReadableMapBuffer> {
+    val readMapBufferList = arrayListOf<ReadableMapBuffer>()
+    var offset = offsetForDynamicData + buffer.getInt(position)
+    val sizeMapBufferList = buffer.getInt(offset)
+    offset += Int.SIZE_BYTES
+    var curLen = 0
+    while (curLen < sizeMapBufferList) {
+      val sizeMapBuffer = buffer.getInt(offset + curLen)
+      val newMapBuffer = ByteArray(sizeMapBuffer)
+      curLen = curLen + Int.SIZE_BYTES
+      buffer.position(offset + curLen)
+      buffer[newMapBuffer, 0, sizeMapBuffer]
+      readMapBufferList.add(ReadableMapBuffer(ByteBuffer.wrap(newMapBuffer)))
+      curLen = curLen + sizeMapBuffer
+    }
+    return readMapBufferList
+  }
+
   private fun getKeyOffsetForBucketIndex(bucketIndex: Int): Int {
     return HEADER_SIZE + BUCKET_SIZE * bucketIndex
   }
@@ -172,6 +190,9 @@ class ReadableMapBuffer : MapBuffer {
   override fun getMapBuffer(key: Int): ReadableMapBuffer =
       readMapBufferValue(getTypedValueOffsetForKey(key, MapBuffer.DataType.MAP))
 
+  override fun getMapBufferList(key: Int): List<ReadableMapBuffer> =
+      readMapBufferListValue(getTypedValueOffsetForKey(key, MapBuffer.DataType.MAP))
+
   override fun hashCode(): Int {
     buffer.rewind()
     return buffer.hashCode()

ReactAndroid/src/main/java/com/facebook/react/common/mapbuffer/WritableMapBuffer.kt

@@ -106,6 +106,8 @@ class WritableMapBuffer : MapBuffer {
 
   override fun getMapBuffer(key: Int): MapBuffer = verifyValue(key, values.get(key))
 
+  override fun getMapBufferList(key: Int): List<MapBuffer> = verifyValue(key, values.get(key))
+
   /** Generalizes verification of the value types based on the requested type. */
   private inline fun <reified T> verifyValue(key: Int, value: Any?): T {
     require(value != null) { "Key not found: $key" }

ReactCommon/react/renderer/mapbuffer/MapBuffer.cpp

@@ -112,6 +112,31 @@ MapBuffer MapBuffer::getMapBuffer(Key key) const {
   return MapBuffer(std::move(value));
 }
 
+std::vector<MapBuffer> MapBuffer::getMapBufferList(MapBuffer::Key key) const {
+  std::vector<MapBuffer> mapBufferList;
+
+  int32_t dynamicDataOffset = getDynamicDataOffset();
+  int32_t offset = getInt(key);
+  int32_t mapBufferListLength = *reinterpret_cast<int32_t const *>(
+      bytes_.data() + dynamicDataOffset + offset);
+  offset = offset + sizeof(uint32_t);
+
+  int32_t curLen = 0;
+  while (curLen < mapBufferListLength) {
+    int32_t mapBufferLength = *reinterpret_cast<int32_t const *>(
+        bytes_.data() + dynamicDataOffset + offset + curLen);
+    curLen = curLen + sizeof(uint32_t);
+    std::vector<uint8_t> value(mapBufferLength);
+    memcpy(
+        value.data(),
+        bytes_.data() + dynamicDataOffset + offset + curLen,
+        mapBufferLength);
+    mapBufferList.emplace_back(std::move(value));
+    curLen = curLen + mapBufferLength;
+  }
+  return mapBufferList;
+}
+
 size_t MapBuffer::size() const {
   return bytes_.size();
 }

ReactCommon/react/renderer/mapbuffer/MapBuffer.h

@@ -126,6 +126,8 @@ class MapBuffer {
   // TODO T83483191: review this declaration
   MapBuffer getMapBuffer(MapBuffer::Key key) const;
 
+  std::vector<MapBuffer> getMapBufferList(MapBuffer::Key key) const;
+
   size_t size() const;
 
   uint8_t const *data() const;

ReactCommon/react/renderer/mapbuffer/MapBufferBuilder.cpp

@@ -114,6 +114,39 @@ void MapBufferBuilder::putMapBuffer(MapBuffer::Key key, MapBuffer const &map) {
       INT_SIZE);
 }
 
+void MapBufferBuilder::putMapBufferList(
+    MapBuffer::Key key,
+    const std::vector<MapBuffer> &mapBufferList) {
+  int32_t offset = dynamicData_.size();
+  int32_t dataSize = 0;
+  for (const MapBuffer &mapBuffer : mapBufferList) {
+    dataSize = dataSize + INT_SIZE + mapBuffer.size();
+  }
+
+  dynamicData_.resize(offset + INT_SIZE, 0);
+  memcpy(dynamicData_.data() + offset, &dataSize, INT_SIZE);
+
+  for (const MapBuffer &mapBuffer : mapBufferList) {
+    int32_t mapBufferSize = mapBuffer.size();
+    int32_t dynamicDataSize = dynamicData_.size();
+    dynamicData_.resize(dynamicDataSize + INT_SIZE + mapBufferSize, 0);
+    // format [length of buffer (int)] + [bytes of MapBuffer]
+    memcpy(dynamicData_.data() + dynamicDataSize, &mapBufferSize, INT_SIZE);
+    // Copy the content of the map into dynamicData_
+    memcpy(
+        dynamicData_.data() + dynamicDataSize + INT_SIZE,
+        mapBuffer.data(),
+        mapBufferSize);
+  }
+
+  // Store Key and pointer to the string
+  storeKeyValue(
+      key,
+      MapBuffer::DataType::Map,
+      reinterpret_cast<uint8_t const *>(&offset),
+      INT_SIZE);
+}
+
 static inline bool compareBuckets(
     MapBuffer::Bucket const &a,
     MapBuffer::Bucket const &b) {

ReactCommon/react/renderer/mapbuffer/MapBufferBuilder.h

@@ -9,6 +9,7 @@
 
 #include <react/debug/react_native_assert.h>
 #include <react/renderer/mapbuffer/MapBuffer.h>
+#include <vector>
 
 namespace facebook {
 namespace react {
@@ -35,6 +36,10 @@ class MapBufferBuilder {
 
   void putMapBuffer(MapBuffer::Key key, MapBuffer const &map);
 
+  void putMapBufferList(
+      MapBuffer::Key key,
+      const std::vector<MapBuffer> &mapBufferList);
+
   MapBuffer build();
 
  private:

ReactCommon/react/renderer/mapbuffer/tests/MapBufferTest.cpp

@@ -6,6 +6,7 @@
  */
 
 #include <memory>
+#include <vector>
 
 #include <gtest/gtest.h>
 #include <react/renderer/mapbuffer/MapBuffer.h>
@@ -150,6 +151,30 @@ TEST(MapBufferTest, testMapEntries) {
   EXPECT_EQ(readMap2.getInt(1), 1234);
 }
 
+TEST(MapBufferTest, testMapListEntries) {
+  std::vector<MapBuffer> mapBufferList;
+  auto builder = MapBufferBuilder();
+  builder.putString(0, "This is a test");
+  builder.putInt(1, 1234);
+  mapBufferList.push_back(builder.build());
+
+  auto builder2 = MapBufferBuilder();
+  builder2.putInt(2, 4321);
+  builder2.putDouble(3, 908.1);
+  mapBufferList.push_back(builder2.build());
+
+  auto builder3 = MapBufferBuilder();
+  builder3.putMapBufferList(5, std::move(mapBufferList));
+  auto map = builder3.build();
+
+  std::vector<MapBuffer> mapBufferList2 = map.getMapBufferList(5);
+
+  EXPECT_EQ(mapBufferList2.size(), 2);
+  EXPECT_EQ(mapBufferList2[0].getString(0), "This is a test");
+  EXPECT_EQ(mapBufferList2[0].getInt(1), 1234);
+  EXPECT_EQ(mapBufferList2[1].getDouble(3), 908.1);
+}
+
 TEST(MapBufferTest, testMapRandomAccess) {
   auto builder = MapBufferBuilder();
   builder.putInt(1234, 4321);