build: made environment access a separate feature

Author: mshabunin

CMakeLists.txt

@@ -536,6 +536,7 @@ OCV_OPTION(ENABLE_CONFIG_VERIFICATION "Fail build if actual configuration doesn'
 OCV_OPTION(OPENCV_ENABLE_MEMALIGN     "Enable posix_memalign or memalign usage" ON)
 OCV_OPTION(OPENCV_DISABLE_FILESYSTEM_SUPPORT "Disable filesystem support" OFF)
 OCV_OPTION(OPENCV_DISABLE_THREAD_SUPPORT "Build the library without multi-threaded code." OFF)
+OCV_OPTION(OPENCV_DISABLE_ENV_SUPPORT "Disable environment variables access (getenv)" (CMAKE_SYSTEM_NAME MATCHES "Windows(CE|Phone|Store)"))
 OCV_OPTION(OPENCV_SEMIHOSTING         "Build the library for semihosting target (Arm). See https://developer.arm.com/documentation/100863/latest." OFF)
 OCV_OPTION(ENABLE_CUDA_FIRST_CLASS_LANGUAGE "Enable CUDA as a first class language, if enabled dependant projects will need to use CMake >= 3.18" OFF
   VISIBLE_IF (WITH_CUDA AND NOT CMAKE_VERSION VERSION_LESS 3.18)

cmake/platforms/OpenCV-WinRT.cmake

@@ -1,6 +1,6 @@
 set(WINRT TRUE)
 
-add_definitions(-DWINRT -DNO_GETENV)
+add_definitions(-DWINRT)
 
 # Making definitions available to other configurations and
 # to filter dependency restrictions at compile time.

cmake/platforms/OpenCV-WindowsCE.cmake

@@ -1 +1 @@
-add_definitions(-DNO_GETENV)
+# empty

doc/tutorials/introduction/env_reference/env_reference.markdown

@@ -59,7 +59,6 @@ import cv2 # variables set after this may not have effect
 
 ## Types
 
-- _non-null_ - set to anything to enable feature, in some cases can be interpreted as other types (e.g. path)
 - _bool_ - `1`, `True`, `true`, `TRUE` / `0`, `False`, `false`, `FALSE`
 - _number_/_size_ - unsigned number, suffixes `MB`, `Mb`, `mb`, `KB`, `Kb`, `kb`
 - _string_ - plain string or can have a structure
@@ -70,17 +69,17 @@ import cv2 # variables set after this may not have effect
 ## General, core
 | name | type | default | description |
 |------|------|---------|-------------|
-| OPENCV_SKIP_CPU_BASELINE_CHECK | non-null | | do not check that current CPU supports all features used by the build (baseline) |
+| OPENCV_SKIP_CPU_BASELINE_CHECK | bool | false | do not check that current CPU supports all features used by the build (baseline) |
 | OPENCV_CPU_DISABLE | `,` or `;`-separated | | disable code branches which use CPU features (dispatched code) |
 | OPENCV_SETUP_TERMINATE_HANDLER | bool | true (Windows) | use std::set_terminate to install own termination handler |
 | OPENCV_LIBVA_RUNTIME | file path | | libva for VA interoperability utils |
 | OPENCV_ENABLE_MEMALIGN | bool | true (except static analysis, memory sanitizer, fuzzying, _WIN32?) | enable aligned memory allocations |
 | OPENCV_BUFFER_AREA_ALWAYS_SAFE | bool | false | enable safe mode for multi-buffer allocations (each buffer separately) |
 | OPENCV_KMEANS_PARALLEL_GRANULARITY | num | 1000 | tune algorithm parallel work distribution parameter `parallel_for_(..., ..., ..., granularity)` |
 | OPENCV_DUMP_ERRORS | bool | true (Debug or Android), false (others) | print extra information on exception (log to Android) |
-| OPENCV_DUMP_CONFIG | non-null | | print build configuration to stderr (`getBuildInformation`) |
+| OPENCV_DUMP_CONFIG | bool | false | print build configuration to stderr (`getBuildInformation`) |
 | OPENCV_PYTHON_DEBUG | bool | false | enable extra warnings in Python bindings |
-| OPENCV_TEMP_PATH | non-null / path | `/tmp/` (Linux), `/data/local/tmp/` (Android), `GetTempPathA` (Windows) | directory for temporary files |
+| OPENCV_TEMP_PATH | path | `/tmp/` (Linux), `/data/local/tmp/` (Android), `GetTempPathA` (Windows) | directory for temporary files |
 | OPENCV_DATA_PATH_HINT | paths | | paths for findDataFile |
 | OPENCV_DATA_PATH | paths | | paths for findDataFile |
 | OPENCV_SAMPLES_DATA_PATH_HINT | paths | | paths for findDataFile |
@@ -272,7 +271,7 @@ Some external dependencies can be detached into a dynamic library, which will be
 | ⭐ OPENCV_FFMPEG_CAPTURE_OPTIONS | string (see note) | | extra options for VideoCapture FFmpeg backend |
 | ⭐ OPENCV_FFMPEG_WRITER_OPTIONS | string (see note) | | extra options for VideoWriter FFmpeg backend |
 | OPENCV_FFMPEG_THREADS | num | | set FFmpeg thread count |
-| OPENCV_FFMPEG_DEBUG | non-null | | enable logging messages from FFmpeg |
+| OPENCV_FFMPEG_DEBUG | bool | false | enable logging messages from FFmpeg |
 | OPENCV_FFMPEG_LOGLEVEL | num | | set FFmpeg logging level |
 | OPENCV_FFMPEG_DLL_DIR | dir path | | directory with FFmpeg plugin (legacy) |
 | OPENCV_FFMPEG_IS_THREAD_SAFE | bool | false | enabling this option will turn off thread safety locks in the FFmpeg backend (use only if you are sure FFmpeg is built with threading support, tested on Linux) |
@@ -286,7 +285,7 @@ Some external dependencies can be detached into a dynamic library, which will be
 | OPENCV_VIDEOIO_MFX_BITRATE_DIVISOR | num | 300 | this option allows to tune encoding bitrate (video quality/size) |
 | OPENCV_VIDEOIO_MFX_WRITER_TIMEOUT | num | 1 | timeout for encoding operation (in seconds) |
 | OPENCV_VIDEOIO_MSMF_ENABLE_HW_TRANSFORMS | bool | true | allow HW-accelerated transformations (DXVA) in MediaFoundation processing graph (may slow down camera probing process) |
-| OPENCV_DSHOW_DEBUG | non-null | | enable verbose logging in the DShow backend |
+| OPENCV_DSHOW_DEBUG | bool | false | enable verbose logging in the DShow backend |
 | OPENCV_DSHOW_SAVEGRAPH_FILENAME | file path | | enable processing graph tump in the DShow backend |
 | OPENCV_VIDEOIO_V4L_RANGE_NORMALIZED | bool | false | use (0, 1) range for properties (V4L) |
 | OPENCV_VIDEOIO_V4L_SELECT_TIMEOUT | num | 10 | timeout for select call (in seconds) (V4L) |
@@ -297,7 +296,7 @@ Some external dependencies can be detached into a dynamic library, which will be
 ### videoio tests
 | name | type | default | description |
 |------|------|---------|-------------|
-| OPENCV_TEST_VIDEOIO_BACKEND_REQUIRE_FFMPEG | | | test app will exit if no FFmpeg backend is available |
+| OPENCV_TEST_VIDEOIO_BACKEND_REQUIRE_FFMPEG | bool | false | test app will exit if no FFmpeg backend is available |
 | OPENCV_TEST_V4L2_VIVID_DEVICE | file path | | path to VIVID virtual camera device for V4L2 test (e.g. `/dev/video5`) |
 | OPENCV_TEST_PERF_CAMERA_LIST | paths | | cameras to use in performance test (waitAny_V4L test) |
 | OPENCV_TEST_CAMERA_%d_FPS | num | | fps to set for N-th camera (0-based index) (waitAny_V4L test) |
@@ -327,7 +326,7 @@ Some external dependencies can be detached into a dynamic library, which will be
 
 | name | type | default | description |
 |------|------|---------|-------------|
-| OPENCV_LEGACY_WAITKEY | non-null | | switch `waitKey` return result (default behavior: `return code & 0xff` (or -1), legacy behavior: `return code`) |
+| OPENCV_LEGACY_WAITKEY | bool | false | switch `waitKey` return result (default behavior: `return code & 0xff` (or -1), legacy behavior: `return code`) |
 | $XDG_RUNTIME_DIR | | | Wayland backend specific - create shared memory-mapped file for interprocess communication (named `opencv-shared-??????`) |
 | OPENCV_HIGHGUI_FB_MODE | string | `FB` | Selects output mode for the framebuffer backend (`FB` - regular frambuffer, `EMU` - emulation, perform internal checks but does nothing, `XVFB` - compatible with _xvfb_ virtual frambuffer) |
 | OPENCV_HIGHGUI_FB_DEVICE | file path | | Path to frambuffer device to use (will be checked first) |

modules/core/CMakeLists.txt

@@ -182,6 +182,10 @@ if(OPENCV_DISABLE_THREAD_SUPPORT)
   ocv_target_compile_definitions(${the_module} PUBLIC "OPENCV_DISABLE_THREAD_SUPPORT=1")
 endif()
 
+if(OPENCV_DISABLE_ENV_SUPPORT)
+  ocv_append_source_file_compile_definitions(${CMAKE_CURRENT_SOURCE_DIR}/src/system.cpp "NO_GETENV")
+endif()
+
 if(OPENCV_SEMIHOSTING)
   ocv_target_compile_definitions(${the_module} PRIVATE "-DOPENCV_SEMIHOSTING")
 endif(OPENCV_SEMIHOSTING)

modules/core/include/opencv2/core/utils/configuration.private.hpp

@@ -12,9 +12,9 @@
 namespace cv { namespace utils {
 
 typedef std::vector<std::string> Paths;
-CV_EXPORTS bool getConfigurationParameterBool(const char* name, bool defaultValue);
-CV_EXPORTS size_t getConfigurationParameterSizeT(const char* name, size_t defaultValue);
-CV_EXPORTS cv::String getConfigurationParameterString(const char* name, const char* defaultValue);
+CV_EXPORTS bool getConfigurationParameterBool(const char* name, bool defaultValue = false);
+CV_EXPORTS size_t getConfigurationParameterSizeT(const char* name, size_t defaultValue = 0);
+CV_EXPORTS std::string getConfigurationParameterString(const char* name, const std::string & defaultValue = std::string());
 CV_EXPORTS Paths getConfigurationParameterPaths(const char* name, const Paths &defaultValue = Paths());
 
 }} // namespace

modules/core/src/ocl.cpp

@@ -1170,10 +1170,10 @@ bool haveOpenCL()
     if (!g_isOpenCLInitialized)
     {
         CV_TRACE_REGION("Init_OpenCL_Runtime");
-        const char* envPath = getenv("OPENCV_OPENCL_RUNTIME");
-        if (envPath)
+        std::string envPath = utils::getConfigurationParameterString("OPENCV_OPENCL_RUNTIME");
+        if (!envPath.empty())
         {
-            if (cv::String(envPath) == "disabled")
+            if (envPath == "disabled")
             {
                 g_isOpenCLAvailable = false;
                 g_isOpenCLInitialized = true;
@@ -2119,24 +2119,18 @@ static bool parseOpenCLDeviceConfiguration(const std::string& configurationStr,
     return true;
 }
 
-#if defined WINRT || defined _WIN32_WCE
-static cl_device_id selectOpenCLDevice(const char* configuration = NULL)
-{
-    CV_UNUSED(configuration)
-    return NULL;
-}
-#else
-static cl_device_id selectOpenCLDevice(const char* configuration = NULL)
+static cl_device_id selectOpenCLDevice(const std::string & configuration_ = std::string())
 {
     std::string platform, deviceName;
     std::vector<std::string> deviceTypes;
 
-    if (!configuration)
-        configuration = getenv("OPENCV_OPENCL_DEVICE");
+    std::string configuration(configuration_);
+    if (configuration.empty())
+        configuration = utils::getConfigurationParameterString("OPENCV_OPENCL_DEVICE");
 
-    if (configuration &&
-            (strcmp(configuration, "disabled") == 0 ||
-             !parseOpenCLDeviceConfiguration(std::string(configuration), platform, deviceTypes, deviceName)
+    if (!configuration.empty() &&
+            (configuration == "disabled" ||
+             !parseOpenCLDeviceConfiguration(configuration, platform, deviceTypes, deviceName)
             ))
         return NULL;
 
@@ -2204,7 +2198,7 @@ static cl_device_id selectOpenCLDevice(const char* configuration = NULL)
         if (!isID)
         {
             deviceTypes.push_back("GPU");
-            if (configuration)
+            if (!configuration.empty())
                 deviceTypes.push_back("CPU");
         }
         else
@@ -2272,7 +2266,7 @@ static cl_device_id selectOpenCLDevice(const char* configuration = NULL)
     }
 
 not_found:
-    if (!configuration)
+    if (configuration.empty())
         return NULL; // suppress messages on stderr
 
     std::ostringstream msg;
@@ -2287,7 +2281,6 @@ static cl_device_id selectOpenCLDevice(const char* configuration = NULL)
     CV_LOG_ERROR(NULL, msg.str());
     return NULL;
 }
-#endif
 
 #ifdef HAVE_OPENCL_SVM
 namespace svm {
@@ -2340,12 +2333,12 @@ static unsigned int getSVMCapabilitiesMask()
     static unsigned int mask = 0;
     if (!initialized)
     {
-        const char* envValue = getenv("OPENCV_OPENCL_SVM_CAPABILITIES_MASK");
-        if (envValue == NULL)
+        const std::string envValue = utils::getConfigurationParameterString("OPENCV_OPENCL_SVM_CAPABILITIES_MASK");
+        if (envValue.empty())
         {
             return ~0U; // all bits 1
         }
-        mask = atoi(envValue);
+        mask = atoi(envValue.c_str());
         initialized = true;
     }
     return mask;
@@ -2482,8 +2475,8 @@ struct Context::Impl
         std::string configuration = configuration_;
         if (configuration_.empty())
         {
-            const char* c = getenv("OPENCV_OPENCL_DEVICE");
-            if (c)
+            const std::string c = utils::getConfigurationParameterString("OPENCV_OPENCL_DEVICE");
+            if (!c.empty())
                 configuration = c;
         }
         Impl* impl = findContext(configuration);
@@ -2494,7 +2487,7 @@ struct Context::Impl
             return impl;
         }
 
-        cl_device_id d = selectOpenCLDevice(configuration.empty() ? NULL : configuration.c_str());
+        cl_device_id d = selectOpenCLDevice(configuration);
         if (d == NULL)
             return NULL;
 

modules/core/src/opencl/runtime/opencl_core.cpp

@@ -44,6 +44,7 @@
 #if defined(HAVE_OPENCL)
 
 #include "opencv2/core.hpp" // CV_Error
+#include "opencv2/core/utils/configuration.private.hpp"
 
 #if defined(HAVE_OPENCL_STATIC)
 #if defined __APPLE__
@@ -64,18 +65,14 @@ CV_SUPPRESS_DEPRECATED_END
 #define ERROR_MSG_CANT_LOAD "Failed to load OpenCL runtime\n"
 #define ERROR_MSG_INVALID_VERSION "Failed to load OpenCL runtime (expected version 1.1+)\n"
 
-static const char* getRuntimePath(const char* defaultPath)
+static std::string getRuntimePath(const std::string & defaultPath)
 {
-    const char* envPath = getenv("OPENCV_OPENCL_RUNTIME");
-    if (envPath)
-    {
-        static const char disabled_str[] = "disabled";
-        if ((strlen(envPath) == sizeof(disabled_str) - 1) &&
-                (memcmp(envPath, disabled_str, sizeof(disabled_str) - 1) == 0))
-            return NULL;
-        return envPath;
-    }
-    return defaultPath;
+    const std::string res = cv::utils::getConfigurationParameterString(
+        "OPENCV_OPENCL_RUNTIME", defaultPath);
+    if (res == "disabled")
+        return std::string();
+    else
+        return res;
 }
 
 #if defined(__APPLE__)
@@ -91,9 +88,9 @@ static void* AppleCLGetProcAddress(const char* name)
         if (!initialized)
         {
             const char* defaultPath = "/System/Library/Frameworks/OpenCL.framework/Versions/Current/OpenCL";
-            const char* path = getRuntimePath(defaultPath);
-            if (path)
-                handle = dlopen(path, RTLD_LAZY | RTLD_GLOBAL);
+            std::string path = getRuntimePath(defaultPath);
+            if (!path.empty())
+                handle = dlopen(path.c_str(), RTLD_LAZY | RTLD_GLOBAL);
             if (handle == NULL)
             {
                 if (path != NULL && path != defaultPath)
@@ -129,13 +126,13 @@ static void* WinGetProcAddress(const char* name)
             handle = GetModuleHandleA("OpenCL.dll");
             if (!handle)
             {
-                const char* defaultPath = "OpenCL.dll";
-                const char* path = getRuntimePath(defaultPath);
-                if (path)
-                    handle = LoadLibraryA(path);
+                const std::string defaultPath = "OpenCL.dll";
+                const std::string path = getRuntimePath(defaultPath);
+                if (!path.empty())
+                    handle = LoadLibraryA(path.c_str());
                 if (!handle)
                 {
-                    if (path != NULL && path != defaultPath)
+                    if (!path.empty() && path != defaultPath)
                         fprintf(stderr, ERROR_MSG_CANT_LOAD);
                 }
                 else if (GetProcAddress(handle, OPENCL_FUNC_TO_CHECK_1_1) == NULL)
@@ -205,8 +202,8 @@ static void* GetProcAddress(const char* name)
             bool foundOpenCL = false;
             for (unsigned int i = 0; i < (sizeof(defaultAndroidPaths)/sizeof(char*)); i++)
             {
-                const char* path = (i==0) ? getRuntimePath(defaultAndroidPaths[i]) : defaultAndroidPaths[i];
-                if (path) {
+                const std::string path = (i==0) ? getRuntimePath(defaultAndroidPaths[i]) : defaultAndroidPaths[i];
+                if (!path.empty()) {
                     handle = GetHandle(path);
                     if (handle) {
                         foundOpenCL = true;
@@ -236,10 +233,10 @@ static void* GetProcAddress(const char* name)
         if (!initialized)
         {
             const char* defaultPath = "libOpenCL.so";
-            const char* path = getRuntimePath(defaultPath);
-            if (path)
+            const std::string path = getRuntimePath(defaultPath);
+            if (!path.empty())
             {
-                handle = GetHandle(path);
+                handle = GetHandle(path.c_str());
                 if (!handle)
                 {
                     if (path == defaultPath)

modules/core/src/parallel/registry_parallel.impl.hpp

@@ -111,7 +111,7 @@ class ParallelBackendRegistry
     bool readPrioritySettings()
     {
         bool hasChanges = false;
-        cv::String prioritized_backends = utils::getConfigurationParameterString("OPENCV_PARALLEL_PRIORITY_LIST", NULL);
+        cv::String prioritized_backends = utils::getConfigurationParameterString("OPENCV_PARALLEL_PRIORITY_LIST");
         if (prioritized_backends.empty())
             return hasChanges;
         CV_LOG_INFO(NULL, "core(parallel): Configured priority list (OPENCV_PARALLEL_PRIORITY_LIST): " << prioritized_backends);