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fixed an annoying, but rare, bug where an |nsCOMPtr| in an ownership ring could |Release()| twice. See the comment in the code for details. r=waterson

Browse Source 
git-svn-id: svn://10.0.0.236/trunk@54061 18797224-902f-48f8-a5cc-f745e15eee43
This commit is contained in:
scc%netscape.com
1999-11-20 08:19:24 +00:00
parent 0aaaa64320
commit de82a95c8c
4 changed files with 74 additions and 78 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
mozilla/xpcom/base/nsCOMPtr.cpp
View File

@@ -50,9 +50,7 @@ nsCOMPtr_base::assign_with_AddRef( nsISupports* rawPtr )
{
if ( rawPtr )
NSCAP_ADDREF(rawPtr);
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = rawPtr;
assign_assuming_AddRef(rawPtr);
}
void
@@ -61,19 +59,12 @@ nsCOMPtr_base::assign_from_helper( const nsCOMPtr_helper& helper, const nsIID& i
nsISupports* newRawPtr;
if ( !NS_SUCCEEDED( helper(iid, NS_REINTERPRET_CAST(void**, &newRawPtr)) ) )
newRawPtr = 0;
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = newRawPtr;
assign_assuming_AddRef(newRawPtr);
}
void**
nsCOMPtr_base::begin_assignment()
{
if ( mRawPtr )
{
NSCAP_RELEASE(mRawPtr);
mRawPtr = 0;
}
assign_assuming_AddRef(0);
return NS_REINTERPRET_CAST(void**, &mRawPtr);
}

61
mozilla/xpcom/base/nsCOMPtr.h
View File

@@ -261,7 +261,7 @@ class NS_EXPORT nsQueryInterface : public nsCOMPtr_helper
private:
nsISupports* mRawPtr;
nsresult* mErrorPtr;
nsresult* mErrorPtr;
};
inline
@@ -373,6 +373,23 @@ class nsCOMPtr_base
protected:
nsISupports* mRawPtr;
void
assign_assuming_AddRef( nsISupports* newPtr )
{
/*
|AddRef()|ing the new value (before entering this function) before
|Release()|ing the old lets us safely ignore the self-assignment case.
We must, however, be careful only to |Release()| _after_ doing the
assignment, in case the |Release()| leads to our _own_ destruction,
which would, in turn, cause an incorrect second |Release()| of our old
pointer. Thank waterson@netscape.com for discovering this.
*/
nsISupports* oldPtr = mRawPtr;
mRawPtr = newPtr;
if ( oldPtr )
NSCAP_RELEASE(oldPtr);
}
};
// template <class T> class nsGetterAddRefs;
@@ -389,6 +406,15 @@ class nsCOMPtr
void assign_from_helper( const nsCOMPtr_helper&, const nsIID& );
void** begin_assignment();
void
assign_assuming_AddRef( T* newPtr )
{
T* oldPtr = mRawPtr;
mRawPtr = newPtr;
if ( oldPtr )
NSCAP_RELEASE(oldPtr);
}
private:
T* mRawPtr;
@@ -495,10 +521,7 @@ class nsCOMPtr
operator=( const nsDontAddRef<T>& rhs )
// assign from |dont_AddRef(expr)|
{
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = rhs.mRawPtr;
assign_assuming_AddRef(rhs.mRawPtr);
NSCAP_ASSERT_NO_QUERY_NEEDED();
return *this;
}
@@ -565,9 +588,7 @@ class nsCOMPtr
#ifndef NSCAP_FEATURE_INLINE_STARTASSIGNMENT
return NS_REINTERPRET_CAST(T**, begin_assignment());
#else
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = 0;
assign_assuming_AddRef(0);
return NS_REINTERPRET_CAST(T**, &mRawPtr);
#endif
}
@@ -658,10 +679,7 @@ class nsCOMPtr<nsISupports>
operator=( const nsDontAddRef<nsISupports>& rhs )
// assign from |dont_AddRef(expr)|
{
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = rhs.mRawPtr;
assign_assuming_AddRef(rhs.mRawPtr);
return *this;
}
@@ -726,9 +744,7 @@ class nsCOMPtr<nsISupports>
#ifndef NSCAP_FEATURE_INLINE_STARTASSIGNMENT
return NS_REINTERPRET_CAST(nsISupports**, begin_assignment());
#else
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = 0;
assign_assuming_AddRef(0);
return NS_REINTERPRET_CAST(nsISupports**, &mRawPtr);
#endif
}
@@ -741,9 +757,7 @@ nsCOMPtr<T>::assign_with_AddRef( nsISupports* rawPtr )
{
if ( rawPtr )
NSCAP_ADDREF(rawPtr);
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = NS_REINTERPRET_CAST(T*, rawPtr);
assign_assuming_AddRef(NS_REINTERPRET_CAST(T*, rawPtr));
}
template <class T>
@@ -753,21 +767,14 @@ nsCOMPtr<T>::assign_from_helper( const nsCOMPtr_helper& helper, const nsIID& aII
T* newRawPtr;
if ( !NS_SUCCEEDED( helper(aIID, NS_REINTERPRET_CAST(void**, &newRawPtr)) ) )
newRawPtr = 0;
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = newRawPtr;
assign_assuming_AddRef(newRawPtr);
}
template <class T>
void**
nsCOMPtr<T>::begin_assignment()
{
if ( mRawPtr )
{
NSCAP_RELEASE(mRawPtr);
mRawPtr = 0;
}
assign_assuming_AddRef(0);
return NS_REINTERPRET_CAST(void**, &mRawPtr);
}
#endif

15
mozilla/xpcom/glue/nsCOMPtr.cpp
View File

@@ -50,9 +50,7 @@ nsCOMPtr_base::assign_with_AddRef( nsISupports* rawPtr )
{
if ( rawPtr )
NSCAP_ADDREF(rawPtr);
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = rawPtr;
assign_assuming_AddRef(rawPtr);
}
void
@@ -61,19 +59,12 @@ nsCOMPtr_base::assign_from_helper( const nsCOMPtr_helper& helper, const nsIID& i
nsISupports* newRawPtr;
if ( !NS_SUCCEEDED( helper(iid, NS_REINTERPRET_CAST(void**, &newRawPtr)) ) )
newRawPtr = 0;
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = newRawPtr;
assign_assuming_AddRef(newRawPtr);
}
void**
nsCOMPtr_base::begin_assignment()
{
if ( mRawPtr )
{
NSCAP_RELEASE(mRawPtr);
mRawPtr = 0;
}
assign_assuming_AddRef(0);
return NS_REINTERPRET_CAST(void**, &mRawPtr);
}

61
mozilla/xpcom/glue/nsCOMPtr.h
View File

@@ -261,7 +261,7 @@ class NS_EXPORT nsQueryInterface : public nsCOMPtr_helper
private:
nsISupports* mRawPtr;
nsresult* mErrorPtr;
nsresult* mErrorPtr;
};
inline
@@ -373,6 +373,23 @@ class nsCOMPtr_base
protected:
nsISupports* mRawPtr;
void
assign_assuming_AddRef( nsISupports* newPtr )
{
/*
|AddRef()|ing the new value (before entering this function) before
|Release()|ing the old lets us safely ignore the self-assignment case.
We must, however, be careful only to |Release()| _after_ doing the
assignment, in case the |Release()| leads to our _own_ destruction,
which would, in turn, cause an incorrect second |Release()| of our old
pointer. Thank waterson@netscape.com for discovering this.
*/
nsISupports* oldPtr = mRawPtr;
mRawPtr = newPtr;
if ( oldPtr )
NSCAP_RELEASE(oldPtr);
}
};
// template <class T> class nsGetterAddRefs;
@@ -389,6 +406,15 @@ class nsCOMPtr
void assign_from_helper( const nsCOMPtr_helper&, const nsIID& );
void** begin_assignment();
void
assign_assuming_AddRef( T* newPtr )
{
T* oldPtr = mRawPtr;
mRawPtr = newPtr;
if ( oldPtr )
NSCAP_RELEASE(oldPtr);
}
private:
T* mRawPtr;
@@ -495,10 +521,7 @@ class nsCOMPtr
operator=( const nsDontAddRef<T>& rhs )
// assign from |dont_AddRef(expr)|
{
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = rhs.mRawPtr;
assign_assuming_AddRef(rhs.mRawPtr);
NSCAP_ASSERT_NO_QUERY_NEEDED();
return *this;
}
@@ -565,9 +588,7 @@ class nsCOMPtr
#ifndef NSCAP_FEATURE_INLINE_STARTASSIGNMENT
return NS_REINTERPRET_CAST(T**, begin_assignment());
#else
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = 0;
assign_assuming_AddRef(0);
return NS_REINTERPRET_CAST(T**, &mRawPtr);
#endif
}
@@ -658,10 +679,7 @@ class nsCOMPtr<nsISupports>
operator=( const nsDontAddRef<nsISupports>& rhs )
// assign from |dont_AddRef(expr)|
{
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = rhs.mRawPtr;
assign_assuming_AddRef(rhs.mRawPtr);
return *this;
}
@@ -726,9 +744,7 @@ class nsCOMPtr<nsISupports>
#ifndef NSCAP_FEATURE_INLINE_STARTASSIGNMENT
return NS_REINTERPRET_CAST(nsISupports**, begin_assignment());
#else
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = 0;
assign_assuming_AddRef(0);
return NS_REINTERPRET_CAST(nsISupports**, &mRawPtr);
#endif
}
@@ -741,9 +757,7 @@ nsCOMPtr<T>::assign_with_AddRef( nsISupports* rawPtr )
{
if ( rawPtr )
NSCAP_ADDREF(rawPtr);
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = NS_REINTERPRET_CAST(T*, rawPtr);
assign_assuming_AddRef(NS_REINTERPRET_CAST(T*, rawPtr));
}
template <class T>
@@ -753,21 +767,14 @@ nsCOMPtr<T>::assign_from_helper( const nsCOMPtr_helper& helper, const nsIID& aII
T* newRawPtr;
if ( !NS_SUCCEEDED( helper(aIID, NS_REINTERPRET_CAST(void**, &newRawPtr)) ) )
newRawPtr = 0;
if ( mRawPtr )
NSCAP_RELEASE(mRawPtr);
mRawPtr = newRawPtr;
assign_assuming_AddRef(newRawPtr);
}
template <class T>
void**
nsCOMPtr<T>::begin_assignment()
{
if ( mRawPtr )
{
NSCAP_RELEASE(mRawPtr);
mRawPtr = 0;
}
assign_assuming_AddRef(0);
return NS_REINTERPRET_CAST(void**, &mRawPtr);
}
#endif