git.c

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/*
 * Implementation of the StdGlobalInterfaceTable object
 *
 * The GlobalInterfaceTable (GIT) object is used to marshal interfaces between
 * threading apartments (contexts). When you want to pass an interface but not
 * as a parameter, it wouldn't get marshalled automatically, so you can use this
 * object to insert the interface into a table, and you get back a cookie.
 * Then when it's retrieved, it'll be unmarshalled into the right apartment.
 *
 * Copyright 2003 Mike Hearn <mike@theoretic.com>
 *
 * 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 <stdarg.h>
 
#define COBJMACROS
 
#include "windef.h"
#include "winbase.h"
#include "winuser.h"
#include "objbase.h"
#include "ole2.h"
#include "winerror.h"
 
#include "compobj_private.h" 
 
#include "wine/list.h"
#include "wine/debug.h"
 
WINE_DEFAULT_DEBUG_CHANNEL(ole);
 
/****************************************************************************
 * StdGlobalInterfaceTable definition
 *
 * This class implements IGlobalInterfaceTable and is a process-wide singleton
 * used for marshalling interfaces between threading apartments using cookies.
 */
 
/* Each entry in the linked list of GIT entries */
typedef struct StdGITEntry
{
  DWORD cookie;
  IID iid;         /* IID of the interface */
  IStream* stream; /* Holds the marshalled interface */
 
  struct list entry;
} StdGITEntry;
 
/* Class data */
typedef struct StdGlobalInterfaceTableImpl
{
  IGlobalInterfaceTable IGlobalInterfaceTable_iface;
 
  struct list list;
  ULONG nextCookie;
  
} StdGlobalInterfaceTableImpl;
 
static IGlobalInterfaceTable *std_git;
 
static CRITICAL_SECTION git_section;
static CRITICAL_SECTION_DEBUG critsect_debug =
{
    0, 0, &git_section,
    { &critsect_debug.ProcessLocksList, &critsect_debug.ProcessLocksList },
      0, 0, { (DWORD_PTR)(__FILE__ ": global interface table") }
};
static CRITICAL_SECTION git_section = { &critsect_debug, -1, 0, 0, 0, 0 };
 
 
static inline StdGlobalInterfaceTableImpl *impl_from_IGlobalInterfaceTable(IGlobalInterfaceTable *iface)
{
  return CONTAINING_RECORD(iface, StdGlobalInterfaceTableImpl, IGlobalInterfaceTable_iface);
}
 
/***
 * A helper function to traverse the list and find the entry that matches the cookie.
 * Returns NULL if not found. Must be called inside git_section critical section.
 */
static StdGITEntry* StdGlobalInterfaceTable_FindEntry(StdGlobalInterfaceTableImpl* This,
                DWORD cookie)
{
  StdGITEntry* e;
 
  TRACE("%p, %#lx.\n", This, cookie);
 
  LIST_FOR_EACH_ENTRY(e, &This->list, StdGITEntry, entry) {
    if (e->cookie == cookie)
      return e;
  }
 
  TRACE("Entry not found\n");
  return NULL;
}
 
/***
 * Here's the boring boilerplate stuff for IUnknown
 */
 
static HRESULT WINAPI
StdGlobalInterfaceTable_QueryInterface(IGlobalInterfaceTable* iface,
               REFIID riid, void** ppvObject)
{
  /* Make sure silly coders can't crash us */
  if (ppvObject == 0) return E_INVALIDARG;
 
  *ppvObject = 0; /* assume we don't have the interface */
 
  /* Do we implement that interface? */
  if (IsEqualIID(&IID_IUnknown, riid) ||
      IsEqualIID(&IID_IGlobalInterfaceTable, riid))
  {
    *ppvObject = iface;
  }
  else
  {
    FIXME("(%s), not supported.\n", debugstr_guid(riid));
    return E_NOINTERFACE;
  }
 
  /* Now inc the refcount */
  IGlobalInterfaceTable_AddRef(iface);
  return S_OK;
}
 
static ULONG WINAPI
StdGlobalInterfaceTable_AddRef(IGlobalInterfaceTable* iface)
{
  return 1;
}
 
static ULONG WINAPI
StdGlobalInterfaceTable_Release(IGlobalInterfaceTable* iface)
{
  return 1;
}
 
/***
 * Now implement the actual IGlobalInterfaceTable interface
 */
 
static HRESULT WINAPI
StdGlobalInterfaceTable_RegisterInterfaceInGlobal(
               IGlobalInterfaceTable* iface, IUnknown* pUnk,
               REFIID riid, DWORD* pdwCookie)
{
  StdGlobalInterfaceTableImpl* const This = impl_from_IGlobalInterfaceTable(iface);
  IStream* stream = NULL;
  HRESULT hres;
  StdGITEntry* entry;
  LARGE_INTEGER zero;
 
  TRACE("iface=%p, pUnk=%p, riid=%s, pdwCookie=0x%p\n", iface, pUnk, debugstr_guid(riid), pdwCookie);
 
  if (pUnk == NULL) return E_INVALIDARG;
  
  /* marshal the interface */
  TRACE("About to marshal the interface\n");
 
  hres = CreateStreamOnHGlobal(0, TRUE, &stream);
  if (hres != S_OK) return hres;
  hres = CoMarshalInterface(stream, riid, pUnk, MSHCTX_INPROC, NULL, MSHLFLAGS_TABLESTRONG);
  if (hres != S_OK)
  {
    IStream_Release(stream);
    return hres;
  }
 
  zero.QuadPart = 0;
  IStream_Seek(stream, zero, STREAM_SEEK_SET, NULL);
 
  entry = malloc(sizeof(*entry));
  if (!entry)
  {
      CoReleaseMarshalData(stream);
      IStream_Release(stream);
      return E_OUTOFMEMORY;
  }
 
  EnterCriticalSection(&git_section);
  
  entry->iid = *riid;
  entry->stream = stream;
  entry->cookie = This->nextCookie;
  This->nextCookie++; /* inc the cookie count */
 
  /* insert the new entry at the end of the list */
  list_add_tail(&This->list, &entry->entry);
 
  /* and return the cookie */
  *pdwCookie = entry->cookie;
  
  LeaveCriticalSection(&git_section);
  
  TRACE("Cookie is %#lx\n", entry->cookie);
  return S_OK;
}
 
static HRESULT WINAPI
StdGlobalInterfaceTable_RevokeInterfaceFromGlobal(
               IGlobalInterfaceTable* iface, DWORD dwCookie)
{
  StdGlobalInterfaceTableImpl* This = impl_from_IGlobalInterfaceTable(iface);
  StdGITEntry* entry;
  HRESULT hr;
 
  TRACE("%p, %#lx.\n", iface, dwCookie);
 
  EnterCriticalSection(&git_section);
 
  entry = StdGlobalInterfaceTable_FindEntry(This, dwCookie);
  if (entry == NULL) {
    TRACE("Entry not found\n");
    LeaveCriticalSection(&git_section);
    return E_INVALIDARG; /* not found */
  }
 
  list_remove(&entry->entry);
 
  LeaveCriticalSection(&git_section);
  
  /* Free the stream */
  hr = CoReleaseMarshalData(entry->stream);
  if (hr != S_OK)
  {
    WARN("Failed to release marshal data, hr = %#lx\n", hr);
    return hr;
  }
  IStream_Release(entry->stream);
 
  free(entry);
  return S_OK;
}
 
static HRESULT WINAPI
StdGlobalInterfaceTable_GetInterfaceFromGlobal(
               IGlobalInterfaceTable* iface, DWORD dwCookie,
               REFIID riid, void **ppv)
{
  StdGlobalInterfaceTableImpl* This = impl_from_IGlobalInterfaceTable(iface);
  StdGITEntry* entry;
  HRESULT hres;
  IStream *stream;
 
  TRACE("%#lx, %s, %p.\n", dwCookie, debugstr_guid(riid), ppv);
 
  EnterCriticalSection(&git_section);
 
  entry = StdGlobalInterfaceTable_FindEntry(This, dwCookie);
  if (entry == NULL) {
    WARN("Entry for cookie %#lx not found\n", dwCookie);
    LeaveCriticalSection(&git_section);
    return E_INVALIDARG;
  }
 
  TRACE("entry=%p\n", entry);
 
  hres = IStream_Clone(entry->stream, &stream);
 
  LeaveCriticalSection(&git_section);
 
  if (hres != S_OK) {
    WARN("Failed to clone stream with error %#lx.\n", hres);
    return hres;
  }
 
  /* unmarshal the interface */
  hres = CoUnmarshalInterface(stream, riid, ppv);
  IStream_Release(stream);
 
  if (hres != S_OK) {
    WARN("Failed to unmarshal stream\n");
    return hres;
  }
 
  TRACE("ppv=%p\n", *ppv);
  return S_OK;
}
 
static const IGlobalInterfaceTableVtbl StdGlobalInterfaceTableImpl_Vtbl =
{
    StdGlobalInterfaceTable_QueryInterface,
    StdGlobalInterfaceTable_AddRef,
    StdGlobalInterfaceTable_Release,
    StdGlobalInterfaceTable_RegisterInterfaceInGlobal,
    StdGlobalInterfaceTable_RevokeInterfaceFromGlobal,
    StdGlobalInterfaceTable_GetInterfaceFromGlobal
};
 
HRESULT WINAPI GlobalInterfaceTable_CreateInstance(IClassFactory *iface, IUnknown *outer, REFIID riid, void **obj)
{
    StdGlobalInterfaceTableImpl *git;
 
    if (!std_git)
    {
        git = malloc(sizeof(*git));
        if (!git) return E_OUTOFMEMORY;
 
        git->IGlobalInterfaceTable_iface.lpVtbl = &StdGlobalInterfaceTableImpl_Vtbl;
        list_init(&git->list);
        git->nextCookie = 0xf100; /* that's where windows starts, so that's where we start */
 
        if (InterlockedCompareExchangePointer((void **)&std_git, &git->IGlobalInterfaceTable_iface, NULL))
        {
            free(git);
        }
        else
            TRACE("Created the GIT %p\n", git);
    }
 
    return IGlobalInterfaceTable_QueryInterface(std_git, riid, obj);
}
 
void release_std_git(void)
{
    StdGlobalInterfaceTableImpl *git;
    StdGITEntry *entry, *entry2;
 
    if (!std_git) return;
 
    git = impl_from_IGlobalInterfaceTable(std_git);
    LIST_FOR_EACH_ENTRY_SAFE(entry, entry2, &git->list, StdGITEntry, entry)
    {
        list_remove(&entry->entry);
 
        CoReleaseMarshalData(entry->stream);
        IStream_Release(entry->stream);
        free(entry);
    }
 
    free(git);
}