cmake now attempts to generate and compile a simple mex file at configure time and reports the working status of the generator and compiler, rather than just naively saying Matlab exists

CMakeLists.txt

@@ -847,13 +847,13 @@ if(NOT ANDROID)
 endif()
 status("    Java tests:"    BUILD_TESTS AND (CAN_BUILD_ANDROID_PROJECTS OR HAVE_opencv_java)            THEN YES ELSE NO)
 
-# ========================== java ==========================
+# ========================= matlab =========================
 status("")
 status("  Matlab:")
-if(NOT MATLAB_FOUND)
-  status("    NOT FOUND")
-else()
-  status("    MEX:"         MATLAB_MEX_SCRIPT  THEN  "${MATLAB_MEX_SCRIPT}"                                    ELSE NO)
+status("    mex:"         MATLAB_MEX_SCRIPT  THEN  "${MATLAB_MEX_SCRIPT}"   ELSE NO)
+if (MATLAB_FOUND)
+  get_property(MEX_WORKS GLOBAL PROPERTY MEX_WORKS)
+  status("    Compiler/generator:" MEX_WORKS    THEN  "Working"                ELSE "Not working (bindings will not be generated)")
 endif()
 
 # ========================== documentation ==========================

modules/matlab/CMakeLists.txt

@@ -1,6 +1,12 @@
 # ----------------------------------------------------------------------------
 #  CMake file for Matlab/Octave support
 # ----------------------------------------------------------------------------
+macro(PREPEND TOKEN OUT IN)
+    foreach(VAR ${IN})
+        string(REGEX REPLACE "^/" "${TOKEN}/" TMP ${VAR})
+        list(APPEND ${OUT} ${TMP})
+    endforeach()
+endmacro()
 
 # make sure we're on a supported architecture with Matlab and python installed
 if (IOS OR ANDROID OR NOT MATLAB_FOUND OR NOT PYTHONLIBS_FOUND)
@@ -13,20 +19,69 @@ ocv_add_module(matlab   BINDINGS opencv_core opencv_imgproc
                                  opencv_highgui opencv_ml opencv_calib3d opencv_photo
                                  opencv_nonfree opencv_calib)
 
-# Add all of the headers we wish to parse
-string(REPLACE "opencv_" "" OPENCV_MATLAB_MODULES "${OPENCV_MODULE_${the_module}_REQ_DEPS};
-                                                   ${OPENCV_MODULE_${the_module}_OPT_DEPS}")
+# add the python generator to the python path
+set(PYPATH_CACHE $ENV{PYTHONPATH})
+set(ENV{PYTHONPATH} ${OPENCV_MODULE_opencv_python_LOCATION}/src2:$ENV{PYTHONPATH})
+
+# get the include path of the Bridge
+prepend("-I" MEX_INCLUDES ${CMAKE_CURRENT_SOURCE_DIR}/include)
+
+# ----------------------------------------------------------------------------
+#  Configure time components
+# ----------------------------------------------------------------------------
+message("-- Trying to generate Matlab code")
+execute_process(
+    COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/generator/gen_matlab_caller.py 
+            ${CMAKE_CURRENT_SOURCE_DIR}/test/rand.hpp ${CMAKE_CURRENT_BINARY_DIR}
+    ERROR_VARIABLE GEN_ERROR
+    OUTPUT_QUIET 
+)
+
+if (GEN_ERROR)
+    message(${GEN_ERROR})
+    message("-- Generating Matlab code failed. Disabling Matlab bindings...")
+    # restore the pythonpath
+    set(ENV{PYTHONPATH} ${PYPATH_CACHE})
+    return()
+else()
+    message("-- Trying to generate Matlab code - OK")
+endif()
+
+# attempt to compile the file using mex
+message("-- Trying to compile mex file")
+execute_process(
+    COMMAND ${MATLAB_MEX_SCRIPT} ${MEX_INCLUDES} ${CMAKE_CURRENT_BINARY_DIR}/src/rand.cpp
+    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/src
+    ERROR_VARIABLE MEX_ERROR
+    OUTPUT_QUIET
+)
+
+if (MEX_ERROR)
+    message(${MEX_ERROR})
+    message("-- Error compiling mex file. Disabling Matlab bindings...")
+    # restore the pythonpath
+    set(ENV{PYTHONPATH} ${PYPATH_CACHE})
+    return()
+else()
+    message("-- Trying to compile mex file - OK")
+endif()
+
+# if we make it here, mex works!
+set_property(GLOBAL PROPERTY MEX_WORKS TRUE)
+
+# ----------------------------------------------------------------------------
+#  Build time components
+# ----------------------------------------------------------------------------
+#string(REPLACE "opencv_" "" OPENCV_MATLAB_MODULES "${OPENCV_MODULE_${the_module}_REQ_DEPS};
+#                                                   ${OPENCV_MODULE_${the_module}_OPT_DEPS}")
 foreach(module ${OPENCV_MATLAB_MODULES})
     if (HAVE_opencv_${module})
         list(APPEND opencv_hdrs "${OPENCV_MODULE_opencv_${module}_LOCATION}/include/opencv2/${module}.hpp")
     endif()
 endforeach()
 
-# add the python generator to the python path
-set(PYPATH_CACHE $ENV{PYTHONPATH})
-set(ENV{PYTHONPATH} ${OPENCV_MODULE_opencv_python_LOCATION}/src2:$ENV{PYTHONPATH})
-
 # synthesise the matlab sources
+# TODO:These should be build-time (ie add_custom_command)
 execute_process(
     COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/generator/gen_matlab_caller.py 
             ${opencv_hdrs} ${CMAKE_CURRENT_BINARY_DIR})

modules/matlab/generator/gen_matlab.py

@@ -18,10 +18,12 @@ class MatlabWrapperGenerator(object):
             # get the file name
             name = os.path.splitext(os.path.basename(file))[0]
             ns[name] = parser.parse(file)
+            print ns[name]
 
         # cleanify the parser output
         parse_tree = ParseTree()
         parse_tree.build(ns)
+        print parse_tree
        
         # setup the template engine
         jtemplate = Environment(loader=PackageLoader('templates', ''), trim_blocks=True, lstrip_blocks=True)

modules/matlab/generator/templates/template_function_base.cpp

@@ -31,14 +31,13 @@ void mexFunction(int nlhs, mxArray* plhs[],
   {% endblock %}
 
   // parse the inputs and outputs
-  std::vector<Bridge> blhs(plhs, plhs+nlhs);
-  std::vector<Bridge> brhs(prhs, prhs+nrhs);
 
   {% block postbridge %}
   {% endblock %}
 
   // call the opencv function
   // [out =] namespace.fun(src1, ..., srcn, dst1, ..., dstn, opt1, ..., optn);
+  {{fun.name}}();
   {% block fcall %}
   {% endblock %}
 

modules/matlab/include/bridge.hpp

@@ -3,13 +3,4 @@
 
 #include "mex.h"
 
-namespace mex {
-  class Bridge {
-  private:
-    mxArray* m_;
-  public:
-    bool valid() { return_ m_ != 0; } const
-    mxArray* toMxArray() { return m_; } const
-  };
-
 #endif

modules/matlab/test/rand.hpp

@@ -0,0 +1,15 @@
+/* 
+ * a rather innocuous-looking function which is actually
+ * part of <cstdlib>, so we can be reasonably sure its
+ * definition will be found
+ */
+#ifndef __OPENCV_MATLAB_TEST_COMPILER_HPP_
+#define __OPENCV_MATLAB_TEST_COMPILER_HPP_
+
+namespace cv {
+
+CV_EXPORTS_W int rand( );
+
+};
+
+#endif

modules/matlab/test/test_compiler.cpp

@@ -1,5 +0,0 @@
-#include <mex.h>
-
-void mexFunction(int nlhs, mxArray* plhs[], int nrhs, const mxArray* prhs[]) {
-
-}