Bug 1156352: Refactor |UnixSocketIOBuffer|, r=kmachulis

This patch moves memory management of |UnixSocketIOBuffer| into
|UnixSocketBuffer| and extends |UnixSocketIOBuffer| with send and
receive interfaces. The class is now the base for all socket-buffer
classes, such as |UnixSocketRawData| and |BluetoothDaemonPDU|.

ipc/bluetooth/BluetoothDaemonConnection.h

@@ -68,8 +68,8 @@ public:
   void GetHeader(uint8_t& aService, uint8_t& aOpcode,
                  uint16_t& aPayloadSize);
 
-  ssize_t Send(int aFd);
-  ssize_t Receive(int aFd);
+  ssize_t Send(int aFd) override;
+  ssize_t Receive(int aFd) override;
 
   int AcquireFd();
 

ipc/unixsocket/SocketBase.cpp

@@ -18,10 +18,10 @@ namespace ipc {
 // UnixSocketIOBuffer
 //
 
-UnixSocketIOBuffer::UnixSocketIOBuffer(const void* aData, size_t aSize)
-: mSize(aSize)
-, mOffset(0)
-, mAvailableSpace(aSize)
+UnixSocketBuffer::UnixSocketBuffer(const void* aData, size_t aSize)
+  : mSize(aSize)
+  , mOffset(0)
+  , mAvailableSpace(aSize)
 {
   MOZ_ASSERT(aData || !mSize);
 
@@ -29,19 +29,19 @@ UnixSocketIOBuffer::UnixSocketIOBuffer(const void* aData, size_t aSize)
   memcpy(mData, aData, mSize);
 }
 
-UnixSocketIOBuffer::UnixSocketIOBuffer(size_t aAvailableSpace)
-: mSize(0)
-, mOffset(0)
-, mAvailableSpace(aAvailableSpace)
+UnixSocketBuffer::UnixSocketBuffer(size_t aAvailableSpace)
+  : mSize(0)
+  , mOffset(0)
+  , mAvailableSpace(aAvailableSpace)
 {
   mData = new uint8_t[mAvailableSpace];
 }
 
-UnixSocketIOBuffer::~UnixSocketIOBuffer()
+UnixSocketBuffer::~UnixSocketBuffer()
 { }
 
 const uint8_t*
-UnixSocketIOBuffer::Consume(size_t aLen)
+UnixSocketBuffer::Consume(size_t aLen)
 {
   if (NS_WARN_IF(GetSize() < aLen)) {
     return nullptr;
@@ -52,7 +52,7 @@ UnixSocketIOBuffer::Consume(size_t aLen)
 }
 
 nsresult
-UnixSocketIOBuffer::Read(void* aValue, size_t aLen)
+UnixSocketBuffer::Read(void* aValue, size_t aLen)
 {
   const uint8_t* data = Consume(aLen);
   if (!data) {
@@ -63,7 +63,7 @@ UnixSocketIOBuffer::Read(void* aValue, size_t aLen)
 }
 
 uint8_t*
-UnixSocketIOBuffer::Append(size_t aLen)
+UnixSocketBuffer::Append(size_t aLen)
 {
   if (((mAvailableSpace - mSize) < aLen)) {
     size_t availableSpace = mAvailableSpace + std::max(mAvailableSpace, aLen);
@@ -78,7 +78,7 @@ UnixSocketIOBuffer::Append(size_t aLen)
 }
 
 nsresult
-UnixSocketIOBuffer::Write(const void* aValue, size_t aLen)
+UnixSocketBuffer::Write(const void* aValue, size_t aLen)
 {
   uint8_t* data = Append(aLen);
   if (!data) {
@@ -89,7 +89,7 @@ UnixSocketIOBuffer::Write(const void* aValue, size_t aLen)
 }
 
 void
-UnixSocketIOBuffer::CleanupLeadingSpace()
+UnixSocketBuffer::CleanupLeadingSpace()
 {
   if (GetLeadingSpace()) {
     if (GetSize() <= GetLeadingSpace()) {
@@ -101,6 +101,21 @@ UnixSocketIOBuffer::CleanupLeadingSpace()
   }
 }
 
+//
+// UnixSocketIOBuffer
+//
+
+UnixSocketIOBuffer::UnixSocketIOBuffer(const void* aData, size_t aSize)
+  : UnixSocketBuffer(aData, aSize)
+{ }
+
+UnixSocketIOBuffer::UnixSocketIOBuffer(size_t aAvailableSpace)
+  : UnixSocketBuffer(aAvailableSpace)
+{ }
+
+UnixSocketIOBuffer::~UnixSocketIOBuffer()
+{ }
+
 //
 // UnixSocketRawData
 //

ipc/unixsocket/SocketBase.h

@@ -23,12 +23,18 @@ namespace mozilla {
 namespace ipc {
 
 //
-// UnixSocketIOBuffer
+// UnixSocketBuffer
 //
 
-class UnixSocketIOBuffer
+/**
+ * |UnixSocketBuffer| implements a FIFO buffer that stores raw socket
+ * data, either for sending on a socket or received from a socket.
+ */
+class UnixSocketBuffer
 {
 public:
+  virtual ~UnixSocketBuffer();
+
   const uint8_t* GetData() const
   {
     return mData + mOffset;
@@ -110,15 +116,13 @@ public:
 protected:
 
   /* This constructor copies aData of aSize bytes length into the
-   * new instance of |UnixSocketIOBuffer|.
+   * new instance of |UnixSocketBuffer|.
    */
-  UnixSocketIOBuffer(const void* aData, size_t aSize);
+  UnixSocketBuffer(const void* aData, size_t aSize);
 
   /* This constructor reserves aAvailableSpace bytes of space.
    */
-  UnixSocketIOBuffer(size_t aAvailableSpace);
-
-  ~UnixSocketIOBuffer();
+  UnixSocketBuffer(size_t aAvailableSpace);
 
   size_t GetLeadingSpace() const
   {
@@ -164,6 +168,46 @@ private:
   nsAutoArrayPtr<uint8_t> mData;
 };
 
+//
+// UnixSocketIOBuffer
+//
+
+/**
+ * |UnixSocketIOBuffer| is a |UnixSocketBuffer| that supports being
+ * received on a socket or being send on a socket. Network protocols
+ * might differ in their exact usage of Unix socket functions and
+ * |UnixSocketIOBuffer| provides a protocol-neutral interface.
+ */
+class UnixSocketIOBuffer : public UnixSocketBuffer
+{
+public:
+  virtual ~UnixSocketIOBuffer();
+
+  /**
+   * Receives data from aFd at the end of the buffer. The returned value
+   * is the number of newly received bytes, or 0 if the peer shut down
+   * its connection, or a negative value on errors.
+   */
+  virtual ssize_t Receive(int aFd) = 0;
+
+  /**
+   * Sends data to aFd from the beginning of the buffer. The returned value
+   * is the number of bytes written, or a negative value on error.
+   */
+  virtual ssize_t Send(int aFd) = 0;
+
+protected:
+
+  /* This constructor copies aData of aSize bytes length into the
+   * new instance of |UnixSocketIOBuffer|.
+   */
+  UnixSocketIOBuffer(const void* aData, size_t aSize);
+
+  /* This constructor reserves aAvailableSpace bytes of space.
+   */
+  UnixSocketIOBuffer(size_t aAvailableSpace);
+};
+
 //
 // UnixSocketRawData
 //
@@ -186,13 +230,13 @@ public:
    * is the number of newly received bytes, or 0 if the peer shut down
    * its connection, or a negative value on errors.
    */
-  ssize_t Receive(int aFd);
+  ssize_t Receive(int aFd) override;
 
   /**
    * Sends data to aFd from the beginning of the buffer. The returned value
    * is the number of bytes written, or a negative value on error.
    */
-  ssize_t Send(int aFd);
+  ssize_t Send(int aFd) override;
 };
 
 enum SocketConnectionStatus {