CallContext.h

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#ifndef CPYCPPYY_CALLCONTEXT_H
#define CPYCPPYY_CALLCONTEXT_H
 
// Standard
#include <vector>
 
#include <sys/types.h>
 
 
namespace CPyCppyy {
 
// small number that allows use of stack for argument passing
const int SMALL_ARGS_N = 8;
 
// convention to pass flag for direct calls (similar to Python's vector calls)
#define DIRECT_CALL ((size_t)1 << (8 * sizeof(size_t) - 1))
 
#ifndef CPYCPPYY_PARAMETER
#define CPYCPPYY_PARAMETER
// general place holder for function parameters
struct Parameter {
    union Value {
        bool                 fBool;
        int8_t               fInt8;
        int16_t              fInt16;
        int32_t              fInt32;
        uint8_t              fUInt8;
        uint16_t             fUInt16;
        uint32_t             fUInt32;
        short                fShort;
        unsigned short       fUShort;
        int                  fInt;
        unsigned int         fUInt;
        long                 fLong;
        intptr_t             fIntPtr;
        unsigned long        fULong;
        long long            fLLong;
        unsigned long long   fULLong;
        int64_t              fInt64;
        uint64_t             fUInt64;
        float                fFloat;
        double               fDouble;
        long double          fLDouble;
        void*                fVoidp;
    } fValue;
    void* fRef;
    char  fTypeCode;
};
#endif // CPYCPPYY_PARAMETER
 
// extra call information
struct CallContext {
    CallContext() : fCurScope(0), fPyContext(nullptr), fFlags(0),
        fArgsVec(nullptr), fNArgs(0), fTemps(nullptr) {}
    CallContext(const CallContext&) = delete;
    CallContext& operator=(const CallContext&) = delete;
    ~CallContext() { if (fTemps) Cleanup(); delete fArgsVec; }
 
    enum ECallFlags {
        kNone                        = 0x000000,
        kIsSorted                    = 0x000001, // if method overload priority determined
        kIsCreator                   = 0x000002, // if method creates python-owned objects
        kIsConstructor               = 0x000004, // if method is a C++ constructor
        kHaveImplicit                = 0x000008, // indicate that implicit converters are available
        kAllowImplicit               = 0x000010, // indicate that implicit conversions are allowed
        kNoImplicit                  = 0x000020, // disable implicit to prevent recursion
        kCallDirect                  = 0x000040, // call wrapped method directly, no inheritance
        kFromDescr                   = 0x000080, // initiated from a descriptor
        kUseHeuristics               = 0x000100, // if method applies heuristics memory policy
        kImplicitSmartPtrConversion  = 0x000200, // enable implicit conversion to smart pointers
        kReleaseGIL                  = 0x000400, // if method should release the GIL
        kSetLifeLine                 = 0x000800, // if return value is part of 'this'
        kNeverLifeLine               = 0x001000, // if the return value is never part of 'this'
        kPyException                 = 0x002000, // Python exception during method execution
        kCppException                = 0x004000, // C++ exception during method execution
        kProtected                   = 0x008000, // if method should return on signals
        kUseFFI                      = 0x010000, // not implemented
        kIsPseudoFunc                = 0x020000, // internal, used for introspection
    };
 
// Policies about memory handling and signal safety
    static bool SetGlobalPolicy(ECallFlags e, bool enabled);
 
    static uint32_t& GlobalPolicyFlags();
 
    void AddTemporary(PyObject* pyobj);
    void Cleanup();
 
    Parameter* GetArgs(size_t sz) {
        if (sz != (size_t)-1) fNArgs = sz;
        if (fNArgs <= SMALL_ARGS_N) return fArgs;
        if (!fArgsVec) fArgsVec = new std::vector<Parameter>();
        fArgsVec->resize(fNArgs);
        return fArgsVec->data();
    }
 
    Parameter* GetArgs() {
        if (fNArgs <= SMALL_ARGS_N) return fArgs;
        return fArgsVec->data();
    }
 
    size_t GetSize() { return fNArgs; }
    size_t GetEncodedSize() { return fNArgs | ((fFlags & kCallDirect) ? DIRECT_CALL : 0); }
 
public:
// info/status
    Cppyy::TCppScope_t fCurScope;
    PyObject*          fPyContext;
    uint32_t           fFlags;
 
private:
    struct Temporary { PyObject* fPyObject; Temporary* fNext; };
 
// payload
    Parameter               fArgs[SMALL_ARGS_N];
    std::vector<Parameter>* fArgsVec;
    size_t                  fNArgs;
    Temporary*              fTemps;
};
 
inline bool IsSorted(uint64_t flags) {
    return flags & CallContext::kIsSorted;
}
 
inline bool IsCreator(uint64_t flags) {
    return flags & CallContext::kIsCreator;
}
 
inline bool IsConstructor(uint64_t flags) {
    return flags & CallContext::kIsConstructor;
}
 
inline bool HaveImplicit(CallContext* ctxt) {
    return ctxt ? (!(ctxt->fFlags & CallContext::kNoImplicit) && (ctxt->fFlags & CallContext::kHaveImplicit)) : false;
}
 
inline bool AllowImplicit(CallContext* ctxt) {
    return ctxt ? (!(ctxt->fFlags & CallContext::kNoImplicit) && (ctxt->fFlags & CallContext::kAllowImplicit)) : false;
}
 
inline bool NoImplicit(CallContext* ctxt) {
    return ctxt ? (ctxt->fFlags & CallContext::kNoImplicit) : false;
}
 
inline bool ReleasesGIL(CallContext* ctxt) {
    return ctxt ? (ctxt->fFlags & CallContext::kReleaseGIL) : false;
}
 
inline bool UseStrictOwnership() {
    using CC = CPyCppyy::CallContext;
    return !(CC::GlobalPolicyFlags() & CC::kUseHeuristics);
}
 
template<CallContext::ECallFlags F>
class CallContextRAII {
public:
    CallContextRAII(CallContext* ctxt) : fCtxt(ctxt) {
        fPrior = fCtxt->fFlags & F;
        fCtxt->fFlags |= F;
    }
    CallContextRAII(const CallContextRAII&) = delete;
    CallContextRAII& operator=(const CallContextRAII&) = delete;
    ~CallContextRAII() {
        if (!fPrior) fCtxt->fFlags &= ~F;
    }
 
private:
    CallContext* fCtxt;
    bool fPrior;
};
 
} // namespace CPyCppyy
 
#endif // !CPYCPPYY_CALLCONTEXT_H