Handle no devices and no platforms better

- Properly catch the exception thrown by getDevices() and if it's a no
  devices found error just return an empty vector.

- Replace C macro for getPlatforms() with a proper function

libethash-cl/ethash_cl_miner.cpp

@@ -78,30 +78,28 @@ ethash_cl_miner::~ethash_cl_miner()
 	finish();
 }
 
-// Quite ugly. Saves us a lot of typing on these static functions
-// since we can't keep the platforms vector in the class (static class/functions)
-//
-// LTODO: With a bit of general refactoring this could go away and platforms
-// be queried only once and kept in the class.
-#define ETHASHCL_GET_PLATFORMS(platforms_, failStmt_)	\
-	do {												\
-		try												\
-		{												\
-			cl::Platform::get(&platforms_);				\
-		}												\
-		catch (cl::Error const& err)					\
-		{												\
-			int errCode = err.err();					\
-			if (errCode == CL_PLATFORM_NOT_FOUND_KHR)	\
-				ETHCL_LOG("No OpenCL platforms found");	\
-			failStmt_;									\
-		}												\
-	} while(0)
+std::vector<cl::Platform> ethash_cl_miner::getPlatforms()
+{
+	vector<cl::Platform> platforms;
+	try
+	{
+		cl::Platform::get(&platforms);
+	}
+	catch(cl::Error const& err)
+	{
+		if (err.err() == CL_PLATFORM_NOT_FOUND_KHR)
+			ETHCL_LOG("No OpenCL platforms found");
+		else
+			throw err;
+	}
+	return platforms;
+}
 
 string ethash_cl_miner::platform_info(unsigned _platformId, unsigned _deviceId)
 {
-	vector<cl::Platform> platforms;
-	ETHASHCL_GET_PLATFORMS(platforms, return string());
+	vector<cl::Platform> platforms = getPlatforms();
+	if (platforms.empty())
+		return string();
 	// get GPU device of the selected platform
 	unsigned platform_num = min<unsigned>(_platformId, platforms.size() - 1);
 	vector<cl::Device> devices = getDevices(platforms, _platformId);
@@ -123,24 +121,35 @@ std::vector<cl::Device> ethash_cl_miner::getDevices(std::vector<cl::Platform> co
 {
 	vector<cl::Device> devices;
 	unsigned platform_num = min<unsigned>(_platformId, _platforms.size() - 1);
-	_platforms[platform_num].getDevices(
-		s_allowCPU ? CL_DEVICE_TYPE_ALL : ETHCL_QUERIED_DEVICE_TYPES,
-		&devices
-	);
+	try
+	{
+		_platforms[platform_num].getDevices(
+			s_allowCPU ? CL_DEVICE_TYPE_ALL : ETHCL_QUERIED_DEVICE_TYPES,
+			&devices
+		);
+	}
+	catch (cl::Error const& err)
+	{
+		// if simply no devices found return empty vector
+		if (err.err() != CL_DEVICE_NOT_FOUND)
+			throw err;
+	}
 	return devices;
 }
 
 unsigned ethash_cl_miner::getNumPlatforms()
 {
-	vector<cl::Platform> platforms;
-	ETHASHCL_GET_PLATFORMS(platforms, return 0);
+	vector<cl::Platform> platforms = getPlatforms();
+	if (platforms.empty())
+		return 0;
 	return platforms.size();
 }
 
 unsigned ethash_cl_miner::getNumDevices(unsigned _platformId)
 {
-	vector<cl::Platform> platforms;
-	ETHASHCL_GET_PLATFORMS(platforms, return 0);
+	vector<cl::Platform> platforms = getPlatforms();
+	if (platforms.empty())
+		return 0;
 
 	vector<cl::Device> devices = getDevices(platforms, _platformId);
 	if (devices.empty())
@@ -200,8 +209,9 @@ unsigned ethash_cl_miner::s_initialGlobalWorkSize = ethash_cl_miner::c_defaultGl
 
 bool ethash_cl_miner::searchForAllDevices(function<bool(cl::Device const&)> _callback)
 {
-	vector<cl::Platform> platforms;
-	ETHASHCL_GET_PLATFORMS(platforms, return false);
+	vector<cl::Platform> platforms = getPlatforms();
+	if (platforms.empty())
+		return false;
 	for (unsigned i = 0; i < platforms.size(); ++i)
 		if (searchForAllDevices(i, _callback))
 			return true;
@@ -211,8 +221,9 @@ bool ethash_cl_miner::searchForAllDevices(function<bool(cl::Device const&)> _cal
 
 bool ethash_cl_miner::searchForAllDevices(unsigned _platformId, function<bool(cl::Device const&)> _callback)
 {
-	vector<cl::Platform> platforms;
-	ETHASHCL_GET_PLATFORMS(platforms, return false);
+	vector<cl::Platform> platforms = getPlatforms();
+	if (platforms.empty())
+		return false;
 	if (_platformId >= platforms.size())
 		return false;
 
@@ -226,16 +237,18 @@ bool ethash_cl_miner::searchForAllDevices(unsigned _platformId, function<bool(cl
 
 void ethash_cl_miner::doForAllDevices(function<void(cl::Device const&)> _callback)
 {
-	vector<cl::Platform> platforms;
-	ETHASHCL_GET_PLATFORMS(platforms, return);
+	vector<cl::Platform> platforms = getPlatforms();
+	if (platforms.empty())
+		return;
 	for (unsigned i = 0; i < platforms.size(); ++i)
 		doForAllDevices(i, _callback);
 }
 
 void ethash_cl_miner::doForAllDevices(unsigned _platformId, function<void(cl::Device const&)> _callback)
 {
-	vector<cl::Platform> platforms;
-	ETHASHCL_GET_PLATFORMS(platforms, return);
+	vector<cl::Platform> platforms = getPlatforms();
+	if (platforms.empty())
+		return;
 	if (_platformId >= platforms.size())
 		return;
 
@@ -273,8 +286,9 @@ bool ethash_cl_miner::init(
 	// get all platforms
 	try
 	{
-		vector<cl::Platform> platforms;
-		ETHASHCL_GET_PLATFORMS(platforms, return false);
+		vector<cl::Platform> platforms = getPlatforms();
+		if (platforms.empty())
+			return false;
 
 		// use selected platform
 		_platformId = min<unsigned>(_platformId, platforms.size() - 1);

libethash-cl/ethash_cl_miner.h

@@ -75,6 +75,7 @@ public:
 private:
 
 	static std::vector<cl::Device> getDevices(std::vector<cl::Platform> const& _platforms, unsigned _platformId);
+	static std::vector<cl::Platform> getPlatforms();
 
 	cl::Context m_context;
 	cl::CommandQueue m_queue;