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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CRYPTO_SCOPED_CAPI_TYPES_H_
#define CRYPTO_SCOPED_CAPI_TYPES_H_
#include <windows.h>
#include <algorithm>
#include "base/logging.h"
#include "base/macros.h"
#include "crypto/wincrypt_shim.h"
namespace crypto {
// Simple destructor for the Free family of CryptoAPI functions, such as
// CryptDestroyHash, which take only a single argument to release.
template <typename CAPIHandle, BOOL (WINAPI *Destroyer)(CAPIHandle)>
struct CAPIDestroyer {
void operator()(CAPIHandle handle) const {
if (handle) {
BOOL ok = Destroyer(handle);
DCHECK(ok);
}
}
};
// Destructor for the Close/Release family of CryptoAPI functions, which take
// a second DWORD parameter indicating flags to use when closing or releasing.
// This includes functions like CertCloseStore or CryptReleaseContext.
template <typename CAPIHandle, BOOL (WINAPI *Destroyer)(CAPIHandle, DWORD),
DWORD flags>
struct CAPIDestroyerWithFlags {
void operator()(CAPIHandle handle) const {
if (handle) {
BOOL ok = Destroyer(handle, flags);
DCHECK(ok);
}
}
};
// scoped_ptr-like class for the CryptoAPI cryptography and certificate
// handles. Because these handles are defined as integer types, and not
// pointers, the existing scoped classes, such as scoped_ptr, are insufficient.
// The semantics are the same as scoped_ptr.
template <class CAPIHandle, typename FreeProc>
class ScopedCAPIHandle {
public:
explicit ScopedCAPIHandle(CAPIHandle handle = NULL) : handle_(handle) {}
~ScopedCAPIHandle() {
reset();
}
void reset(CAPIHandle handle = NULL) {
if (handle_ != handle) {
FreeProc free_proc;
free_proc(handle_);
handle_ = handle;
}
}
operator CAPIHandle() const { return handle_; }
CAPIHandle get() const { return handle_; }
CAPIHandle* receive() {
CHECK(handle_ == NULL);
return &handle_;
}
bool operator==(CAPIHandle handle) const {
return handle_ == handle;
}
bool operator!=(CAPIHandle handle) const {
return handle_ != handle;
}
void swap(ScopedCAPIHandle& b) {
CAPIHandle tmp = b.handle_;
b.handle_ = handle_;
handle_ = tmp;
}
CAPIHandle release() {
CAPIHandle tmp = handle_;
handle_ = NULL;
return tmp;
}
private:
CAPIHandle handle_;
DISALLOW_COPY_AND_ASSIGN(ScopedCAPIHandle);
};
template<class CH, typename FP> inline
bool operator==(CH h, const ScopedCAPIHandle<CH, FP>& b) {
return h == b.get();
}
template<class CH, typename FP> inline
bool operator!=(CH h, const ScopedCAPIHandle<CH, FP>& b) {
return h != b.get();
}
typedef ScopedCAPIHandle<
HCRYPTPROV,
CAPIDestroyerWithFlags<HCRYPTPROV,
CryptReleaseContext, 0> > ScopedHCRYPTPROV;
typedef ScopedCAPIHandle<
HCRYPTKEY, CAPIDestroyer<HCRYPTKEY, CryptDestroyKey> > ScopedHCRYPTKEY;
typedef ScopedCAPIHandle<
HCRYPTHASH, CAPIDestroyer<HCRYPTHASH, CryptDestroyHash> > ScopedHCRYPTHASH;
} // namespace crypto
#endif // CRYPTO_SCOPED_CAPI_TYPES_H_