Moved Discord RPC library's source code to external

Externals/discord-rpc/src/connection_win.cpp

@@ -0,0 +1,128 @@
+#include "connection.h"
+
+#define WIN32_LEAN_AND_MEAN
+#define NOMCX
+#define NOSERVICE
+#define NOIME
+#include <assert.h>
+#include <windows.h>
+
+int GetProcessId()
+{
+    return (int)::GetCurrentProcessId();
+}
+
+struct BaseConnectionWin : public BaseConnection {
+    HANDLE pipe{INVALID_HANDLE_VALUE};
+};
+
+static BaseConnectionWin Connection;
+
+/*static*/ BaseConnection* BaseConnection::Create()
+{
+    return &Connection;
+}
+
+/*static*/ void BaseConnection::Destroy(BaseConnection*& c)
+{
+    auto self = reinterpret_cast<BaseConnectionWin*>(c);
+    self->Close();
+    c = nullptr;
+}
+
+bool BaseConnection::Open()
+{
+    wchar_t pipeName[]{L"\\\\?\\pipe\\discord-ipc-0"};
+    const size_t pipeDigit = sizeof(pipeName) / sizeof(wchar_t) - 2;
+    pipeName[pipeDigit] = L'0';
+    auto self = reinterpret_cast<BaseConnectionWin*>(this);
+    for (;;) {
+        self->pipe = ::CreateFileW(
+          pipeName, GENERIC_READ | GENERIC_WRITE, 0, nullptr, OPEN_EXISTING, 0, nullptr);
+        if (self->pipe != INVALID_HANDLE_VALUE) {
+            self->isOpen = true;
+            return true;
+        }
+
+        auto lastError = GetLastError();
+        if (lastError == ERROR_FILE_NOT_FOUND) {
+            if (pipeName[pipeDigit] < L'9') {
+                pipeName[pipeDigit]++;
+                continue;
+            }
+        }
+        else if (lastError == ERROR_PIPE_BUSY) {
+            if (!WaitNamedPipeW(pipeName, 10000)) {
+                return false;
+            }
+            continue;
+        }
+        return false;
+    }
+}
+
+bool BaseConnection::Close()
+{
+    auto self = reinterpret_cast<BaseConnectionWin*>(this);
+    ::CloseHandle(self->pipe);
+    self->pipe = INVALID_HANDLE_VALUE;
+    self->isOpen = false;
+    return true;
+}
+
+bool BaseConnection::Write(const void* data, size_t length)
+{
+    if (length == 0) {
+        return true;
+    }
+    auto self = reinterpret_cast<BaseConnectionWin*>(this);
+    assert(self);
+    if (!self) {
+        return false;
+    }
+    if (self->pipe == INVALID_HANDLE_VALUE) {
+        return false;
+    }
+    assert(data);
+    if (!data) {
+        return false;
+    }
+    const DWORD bytesLength = (DWORD)length;
+    DWORD bytesWritten = 0;
+    return ::WriteFile(self->pipe, data, bytesLength, &bytesWritten, nullptr) == TRUE &&
+      bytesWritten == bytesLength;
+}
+
+bool BaseConnection::Read(void* data, size_t length)
+{
+    assert(data);
+    if (!data) {
+        return false;
+    }
+    auto self = reinterpret_cast<BaseConnectionWin*>(this);
+    assert(self);
+    if (!self) {
+        return false;
+    }
+    if (self->pipe == INVALID_HANDLE_VALUE) {
+        return false;
+    }
+    DWORD bytesAvailable = 0;
+    if (::PeekNamedPipe(self->pipe, nullptr, 0, nullptr, &bytesAvailable, nullptr)) {
+        if (bytesAvailable >= length) {
+            DWORD bytesToRead = (DWORD)length;
+            DWORD bytesRead = 0;
+            if (::ReadFile(self->pipe, data, bytesToRead, &bytesRead, nullptr) == TRUE) {
+                assert(bytesToRead == bytesRead);
+                return true;
+            }
+            else {
+                Close();
+            }
+        }
+    }
+    else {
+        Close();
+    }
+    return false;
+}