Implement a Vector-based TLVBackingStore (project-chip#32508)

* Implement a Vector-based TLVBackingStore for converting from stream-based input to TLV format

* :Address comments

* Fix for esp32 qemu build

scripts/tools/check_includes_config.py

@@ -167,6 +167,8 @@
     'src/app/PendingResponseTrackerImpl.h': {'unordered_set'},
 
     # Not intended for embedded clients
+    'src/lib/core/TLVVectorWriter.cpp': {'vector'},
+    'src/lib/core/TLVVectorWriter.h': {'vector'},
     'src/lib/support/jsontlv/JsonToTlv.cpp': {'sstream', 'string', 'vector'},
     'src/lib/support/jsontlv/JsonToTlv.h': {'string'},
     'src/lib/support/jsontlv/TlvToJson.h': {'string'},

src/lib/core/BUILD.gn

@@ -187,3 +187,17 @@ static_library("core") {
     "${chip_root}/src/system",
   ]
 }
+
+static_library("vectortlv") {
+  output_name = "libVectorTlv"
+  output_dir = "${root_out_dir}/lib"
+
+  sources = [
+    "TLVVectorWriter.cpp",
+    "TLVVectorWriter.h",
+  ]
+
+  cflags = [ "-Wconversion" ]
+
+  public_deps = [ ":core" ]
+}

src/lib/core/TLVVectorWriter.cpp

@@ -0,0 +1,93 @@
+/*
+ *
+ *    Copyright (c) 2024 Project CHIP Authors
+ *
+ *    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.
+ */
+
+#include <lib/core/TLVVectorWriter.h>
+
+#include <cstdint>
+#include <vector>
+
+#include <lib/core/CHIPError.h>
+#include <lib/core/TLVCommon.h>
+
+namespace chip {
+namespace TLV {
+
+namespace {
+
+constexpr uint32_t kIpv6MtuSize = 1280;
+
+} // namespace
+
+TlvVectorWriter::TlvVectorWriter(std::vector<uint8_t> & buffer) : mVectorBuffer(buffer)
+{
+    Init(mVectorBuffer);
+}
+
+TlvVectorWriter::~TlvVectorWriter() = default;
+
+TlvVectorWriter::TlvVectorBuffer::TlvVectorBuffer(std::vector<uint8_t> & buffer) : mFinalBuffer(buffer) {}
+
+TlvVectorWriter::TlvVectorBuffer::~TlvVectorBuffer() {}
+
+CHIP_ERROR TlvVectorWriter::TlvVectorBuffer::OnInit(TLVWriter & /*writer*/, uint8_t *& bufStart, uint32_t & bufLen)
+{
+    VerifyOrReturnError(mFinalBuffer.empty(), CHIP_ERROR_INCORRECT_STATE);
+
+    ResizeWriteBuffer(bufStart, bufLen);
+
+    return CHIP_NO_ERROR;
+}
+
+CHIP_ERROR TlvVectorWriter::TlvVectorBuffer::GetNewBuffer(TLVWriter & /*writer*/, uint8_t *& bufStart, uint32_t & bufLen)
+{
+    VerifyOrReturnError(!mFinalBuffer.empty(), CHIP_ERROR_INCORRECT_STATE);
+    VerifyOrReturnError(mWritingBuffer.data() == bufStart, CHIP_ERROR_INCORRECT_STATE);
+
+    ResizeWriteBuffer(bufStart, bufLen);
+
+    return CHIP_NO_ERROR;
+}
+
+CHIP_ERROR TlvVectorWriter::TlvVectorBuffer::FinalizeBuffer(TLVWriter & /*writer*/, uint8_t * bufStart, uint32_t bufLen)
+{
+    VerifyOrReturnError(mWritingBuffer.data() == bufStart, CHIP_ERROR_INCORRECT_STATE);
+    VerifyOrReturnError(bufLen <= mWritingBuffer.size(), CHIP_ERROR_BUFFER_TOO_SMALL);
+
+    mWritingBuffer.resize(bufLen);
+
+    mFinalBuffer.insert(mFinalBuffer.end(), mWritingBuffer.begin(), mWritingBuffer.end());
+    mWritingBuffer.resize(0);
+
+    mFinalBuffer.shrink_to_fit();
+
+    return CHIP_NO_ERROR;
+}
+
+void TlvVectorWriter::TlvVectorBuffer::ResizeWriteBuffer(uint8_t *& bufStart, uint32_t & bufLen)
+{
+    VerifyOrReturn(mWritingBuffer.empty());
+
+    mWritingBuffer.resize(kIpv6MtuSize);
+    bufStart = mWritingBuffer.data();
+
+    auto size = mWritingBuffer.size();
+    VerifyOrReturn(size <= std::numeric_limits<uint32_t>::max());
+    bufLen = static_cast<uint32_t>(size);
+}
+
+} // namespace TLV
+} // namespace chip

src/lib/core/TLVVectorWriter.h

@@ -0,0 +1,83 @@
+/*
+ *
+ *    Copyright (c) 2024 Project CHIP Authors
+ *
+ *    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.
+ */
+#pragma once
+
+#include <cstdint>
+#include <vector>
+
+#include <lib/core/CHIPError.h>
+#include <lib/core/TLVBackingStore.h>
+#include <lib/core/TLVCommon.h>
+
+namespace chip {
+namespace TLV {
+
+// Implementation of TLVWriter that writes to a std::vector, automatically
+// resizing the vector as needed when writing.
+// Users of TlvVectorWriter may call any public API of TLVWriter, except for the
+// Init functions.
+// This class is not thread-safe, it must be constructed, used, and destroyed on
+// a single thread.
+class TlvVectorWriter : public TLVWriter
+{
+public:
+    // All data will be written to and read from the provided buffer, which must
+    // outlive this object.
+    TlvVectorWriter(std::vector<uint8_t> & buffer);
+    TlvVectorWriter(const TlvVectorWriter &)             = delete;
+    TlvVectorWriter & operator=(const TlvVectorWriter &) = delete;
+    ~TlvVectorWriter();
+
+private:
+    class TlvVectorBuffer : public TLVBackingStore
+    {
+    public:
+        TlvVectorBuffer(std::vector<uint8_t> & buffer);
+        TlvVectorBuffer(const TlvVectorBuffer &)             = delete;
+        TlvVectorBuffer & operator=(const TlvVectorBuffer &) = delete;
+        ~TlvVectorBuffer() override;
+
+        // TLVBackingStore implementation:
+        CHIP_ERROR OnInit(TLVReader & reader, const uint8_t *& bufStart, uint32_t & bufLen) override
+        {
+            return CHIP_ERROR_NOT_IMPLEMENTED;
+        }
+        CHIP_ERROR GetNextBuffer(TLVReader & reader, const uint8_t *& bufStart, uint32_t & bufLen) override
+        {
+            return CHIP_ERROR_NOT_IMPLEMENTED;
+        }
+        CHIP_ERROR OnInit(TLVWriter & writer, uint8_t *& bufStart, uint32_t & bufLen) override;
+        CHIP_ERROR GetNewBuffer(TLVWriter & writer, uint8_t *& bufStart, uint32_t & bufLen) override;
+        CHIP_ERROR FinalizeBuffer(TLVWriter & writer, uint8_t * bufStart, uint32_t bufLen) override;
+
+    private:
+        void ResizeWriteBuffer(uint8_t *& bufStart, uint32_t & bufLen);
+
+        // mWritingBuffer is the mutable buffer exposed via the TLVBackingStore
+        // interface. When FinalizeBuffer is called the contents of mWritingBuffer
+        // are appended to mFinalBuffer and mWritingBuffer is cleared. This allows
+        // for reading all written data from a single, contiguous buffer
+        // (mFinalBuffer).
+        std::vector<uint8_t> mWritingBuffer;
+        std::vector<uint8_t> & mFinalBuffer;
+    };
+
+    TlvVectorBuffer mVectorBuffer;
+};
+
+} // namespace TLV
+} // namespace chip

src/lib/core/tests/BUILD.gn

@@ -30,12 +30,14 @@ chip_test_suite_using_nltest("tests") {
     "TestOptional.cpp",
     "TestReferenceCounted.cpp",
     "TestTLV.cpp",
+    "TestTLVVectorWriter.cpp",
   ]
 
   cflags = [ "-Wconversion" ]
 
   public_deps = [
     "${chip_root}/src/lib/core",
+    "${chip_root}/src/lib/core:vectortlv",
     "${chip_root}/src/lib/support:test_utils",
     "${chip_root}/src/lib/support:testing_nlunit",
     "${chip_root}/src/platform",