/*
 * Activation contexts
 *
 * Copyright 2004 Jon Griffiths
 * Copyright 2007 Eric Pouech
 * Copyright 2007 Jacek Caban for CodeWeavers
 * Copyright 2007 Alexandre Julliard
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include "config.h"
#include "wine/port.h"

#include <stdarg.h>
#include <stdio.h>

#define NONAMELESSUNION
#define NONAMELESSSTRUCT
#include "ntstatus.h"
#define WIN32_NO_STATUS
#include "winternl.h"
#include "ntdll_misc.h"
#include "wine/debug.h"
#include "wine/unicode.h"

WINE_DEFAULT_DEBUG_CHANNEL(actctx);

#define ACTCTX_FLAGS_ALL (\
 ACTCTX_FLAG_PROCESSOR_ARCHITECTURE_VALID |\
 ACTCTX_FLAG_LANGID_VALID |\
 ACTCTX_FLAG_ASSEMBLY_DIRECTORY_VALID |\
 ACTCTX_FLAG_RESOURCE_NAME_VALID |\
 ACTCTX_FLAG_SET_PROCESS_DEFAULT |\
 ACTCTX_FLAG_APPLICATION_NAME_VALID |\
 ACTCTX_FLAG_SOURCE_IS_ASSEMBLYREF |\
 ACTCTX_FLAG_HMODULE_VALID )

#define ACTCTX_MAGIC       0xC07E3E11

typedef struct _ACTIVATION_CONTEXT
{
    ULONG               magic;
    int                 ref_count;
} ACTIVATION_CONTEXT;


static ACTIVATION_CONTEXT *check_actctx( HANDLE h )
{
    ACTIVATION_CONTEXT *actctx = h;

    if (!h || h == INVALID_HANDLE_VALUE) return NULL;
    switch (actctx->magic)
    {
    case ACTCTX_MAGIC:
        return actctx;
    default:
        return NULL;
    }
}

static inline void actctx_addref( ACTIVATION_CONTEXT *actctx )
{
    interlocked_xchg_add( &actctx->ref_count, 1 );
}

static void actctx_release( ACTIVATION_CONTEXT *actctx )
{
    if (interlocked_xchg_add( &actctx->ref_count, -1 ) == 1)
    {
        actctx->magic = 0;
        RtlFreeHeap( GetProcessHeap(), 0, actctx );
    }
}


/***********************************************************************
 * RtlCreateActivationContext (NTDLL.@)
 *
 * Create an activation context.
 *
 * FIXME: function signature/prototype is wrong
 */
NTSTATUS WINAPI RtlCreateActivationContext( HANDLE *handle, const void *ptr )
{
    const ACTCTXW *pActCtx = ptr;  /* FIXME: not the right structure */
    ACTIVATION_CONTEXT *actctx;

    TRACE("%p %08x\n", pActCtx, pActCtx ? pActCtx->dwFlags : 0);

    if (!pActCtx || pActCtx->cbSize != sizeof(*pActCtx) ||
        (pActCtx->dwFlags & ~ACTCTX_FLAGS_ALL))
        return STATUS_INVALID_PARAMETER;

    if (!(actctx = RtlAllocateHeap( GetProcessHeap(), 0, sizeof(*actctx) )))
        return STATUS_NO_MEMORY;

    actctx->magic = ACTCTX_MAGIC;
    actctx->ref_count = 1;

    *handle = actctx;
    return STATUS_SUCCESS;
}


/***********************************************************************
 *		RtlAddRefActivationContext (NTDLL.@)
 */
void WINAPI RtlAddRefActivationContext( HANDLE handle )
{
    ACTIVATION_CONTEXT *actctx;

    if ((actctx = check_actctx( handle ))) actctx_addref( actctx );
}


/******************************************************************
 *		RtlReleaseActivationContext (NTDLL.@)
 */
void WINAPI RtlReleaseActivationContext( HANDLE handle )
{
    ACTIVATION_CONTEXT *actctx;

    if ((actctx = check_actctx( handle ))) actctx_release( actctx );
}


/******************************************************************
 *		RtlActivateActivationContext (NTDLL.@)
 */
NTSTATUS WINAPI RtlActivateActivationContext( ULONG unknown, HANDLE handle, ULONG_PTR *cookie )
{
    RTL_ACTIVATION_CONTEXT_STACK_FRAME *frame;

    TRACE( "%p %p\n", handle, cookie );

    if (!(frame = RtlAllocateHeap( GetProcessHeap(), 0, sizeof(*frame) )))
        return STATUS_NO_MEMORY;

    frame->Previous = NtCurrentTeb()->ActivationContextStack.ActiveFrame;
    frame->ActivationContext = handle;
    frame->Flags = 0;
    NtCurrentTeb()->ActivationContextStack.ActiveFrame = frame;
    RtlAddRefActivationContext( handle );

    *cookie = (ULONG_PTR)frame;
    return STATUS_SUCCESS;
}


/***********************************************************************
 *		RtlDeactivateActivationContext (NTDLL.@)
 */
void WINAPI RtlDeactivateActivationContext( ULONG flags, ULONG_PTR cookie )
{
    RTL_ACTIVATION_CONTEXT_STACK_FRAME *frame, *top;

    TRACE( "%x %lx\n", flags, cookie );

    /* find the right frame */
    top = NtCurrentTeb()->ActivationContextStack.ActiveFrame;
    for (frame = top; frame; frame = frame->Previous)
        if ((ULONG_PTR)frame == cookie) break;

    if (!frame)
        RtlRaiseStatus( STATUS_SXS_INVALID_DEACTIVATION );

    if (frame != top && !(flags & DEACTIVATE_ACTCTX_FLAG_FORCE_EARLY_DEACTIVATION))
        RtlRaiseStatus( STATUS_SXS_EARLY_DEACTIVATION );

    /* pop everything up to and including frame */
    NtCurrentTeb()->ActivationContextStack.ActiveFrame = frame->Previous;

    while (top != NtCurrentTeb()->ActivationContextStack.ActiveFrame)
    {
        frame = top->Previous;
        RtlReleaseActivationContext( top->ActivationContext );
        RtlFreeHeap( GetProcessHeap(), 0, top );
        top = frame;
    }
}


/******************************************************************
 *		RtlFreeThreadActivationContextStack (NTDLL.@)
 */
void WINAPI RtlFreeThreadActivationContextStack(void)
{
    RTL_ACTIVATION_CONTEXT_STACK_FRAME *frame;

    frame = NtCurrentTeb()->ActivationContextStack.ActiveFrame;
    while (frame)
    {
        RTL_ACTIVATION_CONTEXT_STACK_FRAME *prev = frame->Previous;
        RtlReleaseActivationContext( frame->ActivationContext );
        RtlFreeHeap( GetProcessHeap(), 0, frame );
        frame = prev;
    }
    NtCurrentTeb()->ActivationContextStack.ActiveFrame = NULL;
}


/******************************************************************
 *		RtlGetActiveActivationContext (NTDLL.@)
 */
NTSTATUS WINAPI RtlGetActiveActivationContext( HANDLE *handle )
{
    if (NtCurrentTeb()->ActivationContextStack.ActiveFrame)
    {
        *handle = NtCurrentTeb()->ActivationContextStack.ActiveFrame->ActivationContext;
        RtlAddRefActivationContext( *handle );
    }
    else
        *handle = 0;

    return STATUS_SUCCESS;
}


/******************************************************************
 *		RtlIsActivationContextActive (NTDLL.@)
 */
BOOLEAN WINAPI RtlIsActivationContextActive( HANDLE handle )
{
    RTL_ACTIVATION_CONTEXT_STACK_FRAME *frame;

    for (frame = NtCurrentTeb()->ActivationContextStack.ActiveFrame; frame; frame = frame->Previous)
        if (frame->ActivationContext == handle) return TRUE;
    return FALSE;
}