Chunked mapped memory writer.

src/xenia/base/mapped_memory.h

@@ -31,6 +31,8 @@ class MappedMemory {
   uint8_t* data() const { return reinterpret_cast<uint8_t*>(data_); }
   size_t size() const { return size_; }
 
+  virtual void Flush() = 0;
+
  protected:
   MappedMemory(const std::wstring& path, Mode mode)
       : path_(path), mode_(mode), data_(nullptr), size_(0) {}
@@ -41,6 +43,25 @@ class MappedMemory {
   size_t size_;
 };
 
+class ChunkedMappedMemoryWriter {
+ public:
+  virtual ~ChunkedMappedMemoryWriter() = default;
+
+  static std::unique_ptr<ChunkedMappedMemoryWriter> Open(
+      const std::wstring& path, size_t chunk_size);
+
+  virtual uint8_t* Allocate(size_t length) = 0;
+  virtual void Flush() = 0;
+  virtual void FlushNew() = 0;
+
+ protected:
+  ChunkedMappedMemoryWriter(const std::wstring& path, size_t chunk_size)
+      : path_(path), chunk_size_(chunk_size) {}
+
+  std::wstring path_;
+  size_t chunk_size_;
+};
+
 }  // namespace xe
 
 #endif  // XENIA_BASE_MAPPED_MEMORY_H_

src/xenia/base/mapped_memory_win.cc

@@ -11,6 +11,12 @@
 
 #include <Windows.h>
 
+#include <memory>
+#include <mutex>
+#include <vector>
+
+#include "xenia/base/math.h"
+
 namespace xe {
 
 class Win32MappedMemory : public MappedMemory {
@@ -32,6 +38,10 @@ class Win32MappedMemory : public MappedMemory {
     }
   }
 
+  void Flush() override {
+    FlushViewOfFile(data(), size());
+  }
+
   HANDLE file_handle;
   HANDLE mapping_handle;
 };
@@ -61,11 +71,11 @@ std::unique_ptr<MappedMemory> MappedMemory::Open(const std::wstring& path,
       break;
   }
 
-  SYSTEM_INFO systemInfo;
+  SYSTEM_INFO system_info;
-  GetSystemInfo(&systemInfo);
+  GetSystemInfo(&system_info);
 
   const size_t aligned_offset =
-      offset & ~static_cast<size_t>(systemInfo.dwAllocationGranularity - 1);
+      offset & ~static_cast<size_t>(system_info.dwAllocationGranularity - 1);
   const size_t aligned_length = length + (offset - aligned_offset);
 
   auto mm = std::make_unique<Win32MappedMemory>(path, mode);
@@ -102,4 +112,139 @@ std::unique_ptr<MappedMemory> MappedMemory::Open(const std::wstring& path,
   return std::move(mm);
 }
 
+class Win32ChunkedMappedMemoryWriter : public ChunkedMappedMemoryWriter {
+ public:
+  Win32ChunkedMappedMemoryWriter(const std::wstring& path, size_t chunk_size)
+      : ChunkedMappedMemoryWriter(path, chunk_size) {}
+
+  ~Win32ChunkedMappedMemoryWriter() override {
+    std::lock_guard<std::mutex> lock(mutex_);
+    chunks_.clear();
+  }
+
+  uint8_t* Allocate(size_t length) override {
+    std::lock_guard<std::mutex> lock(mutex_);
+    if (!chunks_.empty()) {
+      uint8_t* result = chunks_.back()->Allocate(length);
+      if (result != nullptr) {
+        return result;
+      }
+    }
+    auto chunk = std::make_unique<Chunk>(chunk_size_);
+    auto chunk_path = path_ + L"." + std::to_wstring(chunks_.size());
+    if (!chunk->Open(chunk_path)) {
+      return nullptr;
+    }
+    uint8_t* result = chunk->Allocate(length);
+    chunks_.push_back(std::move(chunk));
+    return result;
+  }
+
+  void Flush() override {
+    std::lock_guard<std::mutex> lock(mutex_);
+    for (auto& chunk : chunks_) {
+      chunk->Flush();
+    }
+  }
+
+  void FlushNew() override {
+    std::lock_guard<std::mutex> lock(mutex_);
+    for (auto& chunk : chunks_) {
+      chunk->FlushNew();
+    }
+  }
+
+ private:
+  class Chunk {
+   public:
+    Chunk(size_t capacity)
+        : file_handle_(0),
+          mapping_handle_(0),
+          data_(nullptr),
+          offset_(0),
+          capacity_(capacity),
+          last_flush_offset_(0) {}
+
+    ~Chunk() {
+      if (data_) {
+        UnmapViewOfFile(data_);
+      }
+      if (mapping_handle_) {
+        CloseHandle(mapping_handle_);
+      }
+      if (file_handle_) {
+        CloseHandle(file_handle_);
+      }
+    }
+
+    bool Open(const std::wstring& path) {
+      DWORD file_access = GENERIC_READ | GENERIC_WRITE;
+      DWORD file_share = 0;
+      DWORD create_mode = OPEN_EXISTING;
+      DWORD mapping_protect = PAGE_READWRITE;
+      DWORD view_access = FILE_MAP_READ | FILE_MAP_WRITE;
+
+      file_handle_ = CreateFile(path.c_str(), file_access, file_share, nullptr,
+                                create_mode, FILE_ATTRIBUTE_NORMAL, nullptr);
+      if (!file_handle_) {
+        return false;
+      }
+
+      mapping_handle_ =
+          CreateFileMapping(file_handle_, nullptr, mapping_protect, 0,
+                            static_cast<DWORD>(capacity_), nullptr);
+      if (!mapping_handle_) {
+        return false;
+      }
+
+      data_ = reinterpret_cast<uint8_t*>(
+          MapViewOfFile(mapping_handle_, view_access, 0, 0, capacity_));
+      if (!data_) {
+        return false;
+      }
+
+      return true;
+    }
+
+    uint8_t* Allocate(size_t length) {
+      if (capacity_ - offset_ < length) {
+        return nullptr;
+      }
+      uint8_t* result = data_ + offset_;
+      offset_ += length;
+      return result;
+    }
+
+    void Flush() {
+      FlushViewOfFile(data_, offset_);
+    }
+
+    void FlushNew() {
+      FlushViewOfFile(data_ + last_flush_offset_, offset_ - last_flush_offset_);
+      last_flush_offset_ = offset_;
+    }
+
+   private:
+    HANDLE file_handle_;
+    HANDLE mapping_handle_;
+    uint8_t* data_;
+    size_t offset_;
+    size_t capacity_;
+    size_t last_flush_offset_;
+  };
+
+  std::mutex mutex_;
+  std::vector<std::unique_ptr<Chunk>> chunks_;
+};
+
+std::unique_ptr<ChunkedMappedMemoryWriter> ChunkedMappedMemoryWriter::Open(
+    const std::wstring& path, size_t chunk_size) {
+  SYSTEM_INFO system_info;
+  GetSystemInfo(&system_info);
+  size_t aligned_chunk_size =
+      xe::round_up(chunk_size, system_info.dwAllocationGranularity);
+  return std::make_unique<Win32ChunkedMappedMemoryWriter>(path,
+                                                          aligned_chunk_size);
+}
+
 }  // namespace xe