src: avoid manual memory management in inspector

Make the inspector code easier to reason about by restructuring it
to avoid manual memory allocation and copying as much as possible.

An amusing side effect is that it reduces the total amount of memory
used in the test suite.

Before:

    $ valgrind ./out/Release/cctest 2>&1 | grep 'total heap' | cut -c31-
    1,017 allocs, 1,017 frees, 21,695,456 allocated

After:

    $ valgrind ./out/Release/cctest 2>&1 | grep 'total heap' | cut -c31-
    869 allocs, 869 frees, 14,484,641 bytes allocated

PR-URL: nodejs#7906
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

src/inspector_agent.cc

@@ -48,8 +48,8 @@ void PrintDebuggerReadyMessage(int port) {
       port, DEVTOOLS_HASH, port);
 }
 
-bool AcceptsConnection(inspector_socket_t* socket, const char* path) {
-  return strncmp(DEVTOOLS_PATH, path, sizeof(DEVTOOLS_PATH)) == 0;
+bool AcceptsConnection(inspector_socket_t* socket, const std::string& path) {
+  return 0 == path.compare(0, sizeof(DEVTOOLS_PATH) - 1, DEVTOOLS_PATH);
 }
 
 void DisposeInspector(inspector_socket_t* socket, int status) {
@@ -63,10 +63,7 @@ void DisconnectAndDisposeIO(inspector_socket_t* socket) {
 }
 
 void OnBufferAlloc(uv_handle_t* handle, size_t len, uv_buf_t* buf) {
-  if (len > 0) {
-    buf->base = static_cast<char*>(malloc(len));
-    CHECK_NE(buf->base, nullptr);
-  }
+  buf->base = new char[len];
   buf->len = len;
 }
 
@@ -133,18 +130,19 @@ void SendTargentsListResponse(inspector_socket_t* socket, int port) {
   SendHttpResponse(socket, buffer, len);
 }
 
-bool RespondToGet(inspector_socket_t* socket, const char* path, int port) {
+bool RespondToGet(inspector_socket_t* socket, const std::string& path,
+                  int port) {
   const char PATH[] = "/json";
   const char PATH_LIST[] = "/json/list";
   const char PATH_VERSION[] = "/json/version";
   const char PATH_ACTIVATE[] = "/json/activate/";
-  if (!strncmp(PATH_VERSION, path, sizeof(PATH_VERSION))) {
+  if (0 == path.compare(0, sizeof(PATH_VERSION) - 1, PATH_VERSION)) {
     SendVersionResponse(socket);
-  } else if (!strncmp(PATH_LIST, path, sizeof(PATH_LIST)) ||
-             !strncmp(PATH, path, sizeof(PATH)))  {
+  } else if (0 == path.compare(0, sizeof(PATH_LIST) - 1, PATH_LIST) ||
+             0 == path.compare(0, sizeof(PATH) - 1, PATH)) {
     SendTargentsListResponse(socket, port);
-  } else if (!strncmp(path, PATH_ACTIVATE, sizeof(PATH_ACTIVATE) - 1) &&
-             atoi(path + (sizeof(PATH_ACTIVATE) - 1)) == getpid()) {
+  } else if (0 == path.compare(0, sizeof(PATH_ACTIVATE) - 1, PATH_ACTIVATE) &&
+             atoi(path.substr(sizeof(PATH_ACTIVATE) - 1).c_str()) == getpid()) {
     const char TARGET_ACTIVATED[] = "Target activated";
     SendHttpResponse(socket, TARGET_ACTIVATED, sizeof(TARGET_ACTIVATED) - 1);
   } else {
@@ -181,7 +179,7 @@ class AgentImpl {
   static void OnSocketConnectionIO(uv_stream_t* server, int status);
   static bool OnInspectorHandshakeIO(inspector_socket_t* socket,
                                      enum inspector_handshake_event state,
-                                     const char* path);
+                                     const std::string& path);
   static void WriteCbIO(uv_async_t* async);
 
   void WorkerRunIO();
@@ -388,7 +386,6 @@ void AgentImpl::ThreadCbIO(void* agent) {
 void AgentImpl::OnSocketConnectionIO(uv_stream_t* server, int status) {
   if (status == 0) {
     inspector_socket_t* socket = new inspector_socket_t();
-    memset(socket, 0, sizeof(*socket));
     socket->data = server->data;
     if (inspector_accept(server, socket,
                          AgentImpl::OnInspectorHandshakeIO) != 0) {
@@ -399,8 +396,8 @@ void AgentImpl::OnSocketConnectionIO(uv_stream_t* server, int status) {
 
 // static
 bool AgentImpl::OnInspectorHandshakeIO(inspector_socket_t* socket,
-                                   enum inspector_handshake_event state,
-                                   const char* path) {
+                                       enum inspector_handshake_event state,
+                                       const std::string& path) {
   AgentImpl* agent = static_cast<AgentImpl*>(socket->data);
   switch (state) {
   case kInspectorHandshakeHttpGet:
@@ -443,7 +440,7 @@ void AgentImpl::OnRemoteDataIO(inspector_socket_t* socket,
     DisconnectAndDisposeIO(socket);
   }
   if (buf) {
-    free(buf->base);
+    delete[] buf->base;
   }
   pause_cond_.Broadcast(scoped_lock);
 }