From 0b186b1fdab89dc51bf171e66ae6def1d3484cf2 Mon Sep 17 00:00:00 2001
From: Corentin Wallez <cwallez@chromium.org>
Date: Wed, 12 Jul 2017 12:56:05 -0400
Subject: [PATCH] Use feature detection macros everywhere

---
 examples/SampleUtils.cpp              | 25 +++++++++++++---------
 src/backend/opengl/ShaderModuleGL.cpp |  2 +-
 src/common/CMakeLists.txt             |  1 +
 src/common/Math.cpp                   |  6 +++---
 src/common/Platform.h                 | 30 +++++++++++++++++++++++++++
 src/utils/OpenGLBinding.cpp           |  2 +-
 6 files changed, 51 insertions(+), 15 deletions(-)
 create mode 100644 src/common/Platform.h

diff --git a/examples/SampleUtils.cpp b/examples/SampleUtils.cpp
index d89472817b..650fdfd287 100644
--- a/examples/SampleUtils.cpp
+++ b/examples/SampleUtils.cpp
@@ -12,14 +12,17 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include "common/Platform.h"
 #include "utils/BackendBinding.h"
-#include "../src/wire/TerribleCommandBuffer.h"
+#include "wire/TerribleCommandBuffer.h"
 
 // Include Windows.h before GLFW to avoid a redefinition of APIENTRY
-#ifdef _WIN32
+#if defined(NXT_PLATFORM_WINDOWS)
     #include <Windows.h>
+#elif defined(NXT_PLATFORM_POSIX)
+   #include <unistd.h>
 #else
-    #include <unistd.h>
+    #error "Unsupported platform."
 #endif
 
 #include <nxt/nxt.h>
@@ -176,14 +179,16 @@ void DoSwapBuffers() {
     binding->SwapBuffers();
 }
 
-#ifdef _WIN32
-void USleep(uint64_t usecs) {
-    Sleep(static_cast<DWORD>(usecs / 1000));
-}
+#if defined(NXT_PLATFORM_WINDOWS)
+    void USleep(uint64_t usecs) {
+        Sleep(static_cast<DWORD>(usecs / 1000));
+    }
+#elif defined(NXT_PLATFORM_POSIX)
+    void USleep(uint64_t usecs) {
+        usleep(usecs);
+    }
 #else
-void USleep(uint64_t usecs) {
-    usleep(usecs);
-}
+    #error "Implement USleep for your platform."
 #endif
 
 bool ShouldQuit() {
diff --git a/src/backend/opengl/ShaderModuleGL.cpp b/src/backend/opengl/ShaderModuleGL.cpp
index 8f3e0c8569..7e7360f944 100644
--- a/src/backend/opengl/ShaderModuleGL.cpp
+++ b/src/backend/opengl/ShaderModuleGL.cpp
@@ -49,7 +49,7 @@ namespace opengl {
         spirv_cross::CompilerGLSL::Options options;
 
         // TODO(cwallez@chromium.org): discover the backing context version and use that.
-#if defined(__APPLE__)
+#if defined(NXT_PLATFORM_APPLE)
         options.version = 410;
 #else
         options.version = 450;
diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
index de20bb2a84..2135389bc1 100644
--- a/src/common/CMakeLists.txt
+++ b/src/common/CMakeLists.txt
@@ -21,6 +21,7 @@ list(APPEND COMMON_SOURCES
     ${COMMON_DIR}/Compiler.h
     ${COMMON_DIR}/Math.cpp
     ${COMMON_DIR}/Math.h
+    ${COMMON_DIR}/Platform.h
     ${COMMON_DIR}/Serial.h
     ${COMMON_DIR}/SerialQueue.h
 )
diff --git a/src/common/Math.cpp b/src/common/Math.cpp
index 0c6a7a6c3b..6c542c7f63 100644
--- a/src/common/Math.cpp
+++ b/src/common/Math.cpp
@@ -16,13 +16,13 @@
 
 #include "common/Assert.h"
 
-#if defined(_WIN32) || defined(_WIN64)
+#if defined(NXT_COMPILER_MSVC)
     #include <intrin.h>
 #endif
 
 uint32_t ScanForward(uint32_t bits) {
     ASSERT(bits != 0);
-    #if defined(_WIN32) || defined(_WIN64)
+    #if defined(NXT_COMPILER_MSVC)
         unsigned long firstBitIndex = 0ul;
         unsigned char ret = _BitScanForward(&firstBitIndex, bits);
         ASSERT(ret != 0);
@@ -34,7 +34,7 @@ uint32_t ScanForward(uint32_t bits) {
 
 uint32_t Log2(uint32_t value) {
     ASSERT(value != 0);
-    #if defined(_WIN32) || defined(_WIN64)
+    #if defined(NXT_COMPILER_MSVC)
         unsigned long firstBitIndex = 0ul;
         unsigned char ret = _BitScanReverse(&firstBitIndex, value);
         ASSERT(ret != 0);
diff --git a/src/common/Platform.h b/src/common/Platform.h
new file mode 100644
index 0000000000..1c7c8454cb
--- /dev/null
+++ b/src/common/Platform.h
@@ -0,0 +1,30 @@
+// Copyright 2017 The NXT 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.
+
+#ifndef COMMON_PLATFORM_H_
+#define COMMON_PLATFORM_H_
+
+#if defined(_WIN32) || defined(_WIN64)
+    #define NXT_PLATFORM_WINDOWS 1
+#elif defined(__linux__)
+    #define NXT_PLATFORM_LINUX 1
+    #define NXT_PLATFORM_POSIX 1
+#elif defined(__APPLE__)
+    #define NXT_PLATFORM_APPLE 1
+    #define NXT_PLATFORM_POSIX 1
+#else
+    #error "Unsupported platform."
+#endif
+
+#endif // COMMON_PLATFORM_H_
diff --git a/src/utils/OpenGLBinding.cpp b/src/utils/OpenGLBinding.cpp
index cc01fbe8b5..c2f67b68ee 100644
--- a/src/utils/OpenGLBinding.cpp
+++ b/src/utils/OpenGLBinding.cpp
@@ -29,7 +29,7 @@ namespace utils {
     class OpenGLBinding : public BackendBinding {
         public:
             void SetupGLFWWindowHints() override {
-                #ifdef __APPLE__
+                #if defined(NXT_PLATFORM_APPLE)
                     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
                     glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
                     glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GLFW_TRUE);