ocl: update compiled programs

- minimize library initialization time (lazy calculations of program hash)
- LRU cache of in-memory compiled programs

modules/core/include/opencv2/core/ocl.hpp

@@ -627,17 +627,18 @@ protected:
 class CV_EXPORTS ProgramSource
 {
 public:
-    typedef uint64 hash_t;
+    typedef uint64 hash_t; // deprecated
 
     ProgramSource();
-    explicit ProgramSource(const String& prog);
-    explicit ProgramSource(const char* prog);
+    explicit ProgramSource(const String& module, const String& name, const String& codeStr, const String& codeHash);
+    explicit ProgramSource(const String& prog); // deprecated
+    explicit ProgramSource(const char* prog); // deprecated
     ~ProgramSource();
     ProgramSource(const ProgramSource& prog);
     ProgramSource& operator = (const ProgramSource& prog);
 
     const String& source() const;
-    hash_t hash() const;
+    hash_t hash() const; // deprecated
 
 protected:
     struct Impl;

modules/core/include/opencv2/core/ocl_genbase.hpp

@@ -42,23 +42,28 @@
 #ifndef OPENCV_OPENCL_GENBASE_HPP
 #define OPENCV_OPENCL_GENBASE_HPP
 
-namespace cv
-{
-namespace ocl
-{
-
 //! @cond IGNORED
 
-struct ProgramEntry
+namespace cv {
+namespace ocl {
+
+class ProgramSource;
+
+namespace internal {
+
+struct CV_EXPORTS ProgramEntry
 {
+    const char* module;
     const char* name;
-    const char* programStr;
+    const char* programCode;
     const char* programHash;
+    ProgramSource* pProgramSource;
+
+    operator ProgramSource& () const;
 };
 
+} } } // namespace
+
 //! @endcond
 
-}
-}
-
 #endif