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/*
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
// @file Contains utility classes that make it easier to use SecBuffers
#ifndef WEBRTC_BASE_SEC_BUFFER_H__
#define WEBRTC_BASE_SEC_BUFFER_H__
namespace rtc {
// A base class for CSecBuffer<T>. Contains
// all implementation that does not require
// template arguments.
class CSecBufferBase : public SecBuffer {
public:
CSecBufferBase() {
Clear();
}
// Uses the SSPI to free a pointer, must be
// used for buffers returned from SSPI APIs.
static void FreeSSPI(void *ptr) {
if ( ptr ) {
SECURITY_STATUS status;
status = ::FreeContextBuffer(ptr);
ASSERT(SEC_E_OK == status); // "Freeing context buffer"
}
}
// Deletes a buffer with operator delete
static void FreeDelete(void *ptr) {
delete [] reinterpret_cast<char*>(ptr);
}
// A noop delete, for buffers over other
// people's memory
static void FreeNone(void *ptr) {
}
protected:
// Clears the buffer to EMPTY & NULL
void Clear() {
this->BufferType = SECBUFFER_EMPTY;
this->cbBuffer = 0;
this->pvBuffer = NULL;
}
};
// Wrapper class for SecBuffer to take care
// of initialization and destruction.
template <void (*pfnFreeBuffer)(void *ptr)>
class CSecBuffer: public CSecBufferBase {
public:
// Initializes buffer to empty & NULL
CSecBuffer() {
}
// Frees any allocated memory
~CSecBuffer() {
Release();
}
// Frees the buffer appropriately, and re-nulls
void Release() {
pfnFreeBuffer(this->pvBuffer);
Clear();
}
private:
// A placeholder function for compile-time asserts on the class
void CompileAsserts() {
// never invoked...
assert(false); // _T("Notreached")
// This class must not extend the size of SecBuffer, since
// we use arrays of CSecBuffer in CSecBufferBundle below
cassert(sizeof(CSecBuffer<SSPIFree> == sizeof(SecBuffer)));
}
};
// Contains all generic implementation for the
// SecBufferBundle class
class SecBufferBundleBase {
public:
};
// A template class that bundles a SecBufferDesc with
// one or more SecBuffers for convenience. Can take
// care of deallocating buffers appropriately, as indicated
// by pfnFreeBuffer function.
// By default does no deallocation.
template <int num_buffers,
void (*pfnFreeBuffer)(void *ptr) = CSecBufferBase::FreeNone>
class CSecBufferBundle : public SecBufferBundleBase {
public:
// Constructs a security buffer bundle with num_buffers
// buffers, all of which are empty and nulled.
CSecBufferBundle() {
desc_.ulVersion = SECBUFFER_VERSION;
desc_.cBuffers = num_buffers;
desc_.pBuffers = buffers_;
}
// Frees all currently used buffers.
~CSecBufferBundle() {
Release();
}
// Accessor for the descriptor
PSecBufferDesc desc() {
return &desc_;
}
// Accessor for the descriptor
PSecBufferDesc desc() const {
return &desc_;
}
// returns the i-th security buffer
SecBuffer &operator[] (size_t num) {
ASSERT(num < num_buffers); // "Buffer index out of bounds"
return buffers_[num];
}
// returns the i-th security buffer
const SecBuffer &operator[] (size_t num) const {
ASSERT(num < num_buffers); // "Buffer index out of bounds"
return buffers_[num];
}
// Frees all non-NULL security buffers,
// using the deallocation function
void Release() {
for ( size_t i = 0; i < num_buffers; ++i ) {
buffers_[i].Release();
}
}
private:
// Our descriptor
SecBufferDesc desc_;
// Our bundled buffers, each takes care of its own
// initialization and destruction
CSecBuffer<pfnFreeBuffer> buffers_[num_buffers];
};
} // namespace rtc
#endif // WEBRTC_BASE_SEC_BUFFER_H__