Source code of Windows XP (NT5)
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/*++
Copyright (c) 2001 Microsoft Corporation
Module Name:
com.c
Abstract:
Implements the required code for a COM server. This module is specific to
the COM interfaces exposed by osuninst.dll
Author:
Jim Schmidt (jimschm) 21-Feb-2001
Revision History:
<alias> <date> <comments>
--*/
#include "pch.h"
#include "compguid.h"
#include "com.h"
#include "undop.h"
//
// Globals
//
INT g_DllObjects;
INT g_DllLocks;
//
// Implementation
//
STDAPI
DllGetClassObject (
IN REFCLSID ClassId,
IN REFIID InterfaceIdRef,
OUT PVOID *InterfacePtr
)
/*++
Routine Description:
DllGetClassObject is the DLL-to-COM connection. It is exported from the DLL,
so that COM can call it with CoGetClassObject. COM is the only one who calls
this entry point, and finds the dll through registration of the CLSID in
HKCR.
Arguments:
ClassId - Specifies the class factory desired. This arg allows a single DLL
to implement multiple interfaces.
InterfaceIdRef - Specifies the interface the caller wants on the class
object, usually IID_ClassFactory.
InterfacePtr - Receives the interface pointer, or NULL if an error occurs.
Return Value:
E_INVALIDARG - The caller specified an invalid argument
E_OUTOFMEMORY - Failed to alloc memory for interface
E_UNEXPECTED - Some random problem
S_OK - Success
CLASS_E_CLASSNOTAVAILABLE - Requested class is not supported
--*/
{
BOOL result = FALSE;
HRESULT hr = S_OK;
PUNINSTALLCLASSFACTORY uninstallClassFactory = NULL;
__try {
DeferredInit();
//
// Initialize out arg
//
__try {
*InterfacePtr = NULL;
}
__except(1) {
hr = E_INVALIDARG;
}
if (hr != S_OK) {
DEBUGMSG ((DBG_ERROR, __FUNCTION__ ": Invalid InterfacePtr arg"));
__leave;
}
//
// Is this a request for a disk cleanup class? If not, fail with
// CLASS_E_CLASSNOTAVAILABLE.
//
if (!IsEqualCLSID (ClassId, CLSID_UninstallCleaner)) {
DEBUGMSG ((DBG_ERROR, "Uninstall: Requested class not supported"));
hr = CLASS_E_CLASSNOTAVAILABLE;
__leave;
}
//
// Return our IClassFactory for making CCompShellExt objects
//
uninstallClassFactory = new CUninstallClassFactory ();
if (!uninstallClassFactory) {
hr = E_OUTOFMEMORY;
__leave;
}
//
// Test if our class factory support the requested interface
//
hr = uninstallClassFactory->QueryInterface (InterfaceIdRef, InterfacePtr);
}
__finally {
if (FAILED (hr) && uninstallClassFactory) {
//
// failure -- clean up object
//
delete uninstallClassFactory;
}
}
return hr;
}
STDAPI
DllCanUnloadNow (
VOID
)
/*++
Routine Description:
Indicatates if this DLL is in use or not. If it is not in use, COM will
unload it.
Arguments:
None.
Return Value:
S_OK - The DLL is not in use
S_FALSE - The DLL is used at least once
--*/
{
if (g_DllObjects || g_DllLocks) {
return S_FALSE;
}
return S_OK;
}
/*++
Routine Descriptions:
This constructor is a generic class factory that supports multiple object
types. Upon creation, the object interface pointer ref count is set to zero,
and the global number of objects for the dll is incremented.
The destructor simply decrements the DLL object count.
Arguments:
None.
Return Value:
None.
--*/
CUninstallClassFactory::CUninstallClassFactory (
VOID
)
{
//
// -Initialize the interface pointer count
// -Increment the DLL's global count of objects
//
_References = 0;
g_DllObjects++;
}
CUninstallClassFactory::~CUninstallClassFactory (
VOID
)
{
g_DllObjects--;
}
STDMETHODIMP
CUninstallClassFactory::QueryInterface (
IN REFIID InterfaceIdRef,
OUT PVOID *InterfacePtr
)
{
HRESULT hr = S_OK;
DEBUGMSG ((DBG_VERBOSE, __FUNCTION__ ": Entering"));
__try {
//
// Initialize out arg
//
__try {
*InterfacePtr = NULL;
}
__except(1) {
hr = E_INVALIDARG;
}
if (hr != S_OK) {
DEBUGMSG ((DBG_ERROR, __FUNCTION__ ": Invalid InterfacePtr arg"));
__leave;
}
//
// Test for the supported interface
//
if (IsEqualIID (InterfaceIdRef, IID_IUnknown)) {
DEBUGMSG ((DBG_VERBOSE, "Caller requested IUnknown"));
*InterfacePtr = (LPUNKNOWN)(LPCLASSFACTORY) this;
AddRef();
__leave;
}
if (IsEqualIID (InterfaceIdRef, IID_IClassFactory)) {
DEBUGMSG ((DBG_VERBOSE, "Caller requested IClassFactory"));
*InterfacePtr = (LPCLASSFACTORY)this;
AddRef();
__leave;
}
DEBUGMSG ((DBG_WARNING, "Caller requested unknown interface"));
hr = E_NOINTERFACE;
}
__finally {
}
DEBUGMSG ((DBG_VERBOSE, __FUNCTION__ ": Leaving"));
return hr;
}
/*++
Routine Description:
AddRef is the standard IUnknown member function that increments the object
reference count.
Release is the standard IUnknown member function that decrements the object
reference count.
Arguments:
None.
Return Value:
The number of interface references.
--*/
STDMETHODIMP_(ULONG)
CUninstallClassFactory::AddRef (
VOID
)
{
return ++_References;
}
STDMETHODIMP_(ULONG)
CUninstallClassFactory::Release (
VOID
)
{
if (!_References) {
DEBUGMSG ((DBG_ERROR, "Can't release because there are no references"));
} else {
_References--;
if (!_References) {
delete this;
return 0;
}
}
return _References;
}
STDMETHODIMP
CUninstallClassFactory::CreateInstance (
IN LPUNKNOWN IUnknownOuterInterfacePtr,
IN REFIID InterfaceIdRef,
OUT PVOID * InterfacePtr
)
/*++
Routine Description:
CreateInstance establishes an object.
Arguments:
IUnknownOuterInterfacePtr - Specifies the IUnknown interface that
is the outer layer in objects derrived from us. This happens only when
additional objects inherit out interfaces.
InterfaceIdRef - Specifies the interface that the caller wants to
instantiate
InterfacePtr - Receives the pointer to the interface, or NULL on an error
Return Value:
S_OK - The object was created and its reference is returned in InterfacePtr
E_OUTOFMEMORY - Not enough memory available to instantiate the object
E_INVALIDARG - The caller specified an invalid InterfacePtr arg
E_UNEXPECTED - Some random error condition was encountered
E_NOINTERFACE - InterfaceIdRef is not supported
--*/
{
HRESULT hr = S_OK;
PUNINSTALLDISKCLEANER uninstallDiskCleaner = NULL;
__try {
//
// Initialize out arg
//
__try {
*InterfacePtr = NULL;
}
__except(1) {
hr = E_INVALIDARG;
}
if (hr != S_OK) {
DEBUGMSG ((DBG_ERROR, __FUNCTION__ ": Invalid InterfacePtr arg"));
__leave;
}
//
// Shell extensions typically don't support aggregation (inheritance)
//
if (IUnknownOuterInterfacePtr) {
hr = CLASS_E_NOAGGREGATION;
__leave;
}
//
// Create the disk cleaner object
//
if (IsEqualIID (InterfaceIdRef, IID_IEmptyVolumeCache)) {
DEBUGMSG ((DBG_VERBOSE, __FUNCTION__ ": Creating CUninstallDiskCleaner"));
uninstallDiskCleaner = new CUninstallDiskCleaner();
if (!uninstallDiskCleaner) {
hr = E_OUTOFMEMORY;
__leave;
}
hr = uninstallDiskCleaner->QueryInterface (InterfaceIdRef, InterfacePtr);
__leave;
}
DEBUGMSG ((DBG_ERROR, __FUNCTION__ ": Unknown InterfaceIdRef"));
hr = E_NOINTERFACE;
}
__finally {
if (FAILED(hr)) {
if (uninstallDiskCleaner) {
delete uninstallDiskCleaner;
}
}
}
return hr;
}
STDMETHODIMP
CUninstallClassFactory::LockServer (
IN BOOL Lock
)
/*++
Routine Description:
LockServer is the standard IUnknown interface that is used to keep a server
in memory. Its implementation tracks the lock count in a global.
Arguments:
Lock - Specifies TRUE to increment the loc count, or FALSE to decrement it.
Return Value:
S_OK - Server was locked (or unlocked)
E_FAIL - No locks exist/can't unlock
--*/
{
HRESULT hr = S_OK;
if (Lock) {
g_DllLocks++;
} else {
if (g_DllLocks) {
g_DllLocks--;
} else {
DEBUGMSG ((DBG_ERROR, __FUNCTION__ ": Attempt to unlock when no locks exist"));
hr = E_FAIL;
}
}
return hr;
}