[PATCH] Add _sticky variants of references

[Sam Liddicott]

Sticky references will not be considered a problem when talloc_free
is called. Non-sticky references will.
---
 lib/talloc/talloc.c |   27 +++++++++++++++++++++++++--
 lib/talloc/talloc.h |    2 ++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/lib/talloc/talloc.c b/lib/talloc/talloc.c
index 76351fe..9f21ca4 100644
--- a/lib/talloc/talloc.c
+++ b/lib/talloc/talloc.c
@@ -7,6 +7,7 @@
 
    Copyright (C) Andrew Tridgell 2004
    Copyright (C) Stefan Metzmacher 2006
+   Copyright (C) Sam Liddicott 2009
    
      ** NOTE! The following LGPL license applies to the talloc
      ** library. This does NOT imply that all of Samba is released
@@ -110,6 +111,7 @@ static inline int _talloc_free(void *ptr);
 struct talloc_reference_handle {
 	struct talloc_reference_handle *next, *prev;
 	void *ptr;
+	bool sticky;
 };
 
 typedef int (*talloc_destructor_t)(void *);
@@ -410,7 +412,7 @@ void _talloc_set_destructor(const void *ptr, int (*destructor)(void *))
 }
 
 /*
-  increase the reference count on a piece of memory. 
+  slippy increase the reference count on a piece of memory.
 */
 int talloc_increase_ref_count(const void *ptr)
 {
@@ -421,6 +423,17 @@ int talloc_increase_ref_count(const void *ptr)
 }
 
 /*
+  sticky increase the reference count on a piece of memory.
+*/
+int talloc_increase_ref_count_sticky(const void *ptr)
+{
+	if (unlikely(!talloc_reference_sticky(null_context, ptr))) {
+		return -1;
+	}
+	return 0;
+}
+
+/*
   helper for talloc_reference()
 
   this is referenced by a function pointer and should not be inline
@@ -473,7 +486,7 @@ static inline void *_talloc_named_const(const void *context, size_t size, const
   same underlying data, and you want to be able to free the two instances separately,
   and in either order
 */
-void *_talloc_reference(const void *context, const void *ptr)
+void *__talloc_reference(const void *context, const void *ptr, bool sticky)
 {
 	struct talloc_chunk *tc;
 	struct talloc_reference_handle *handle;
@@ -491,9 +504,19 @@ void *_talloc_reference(const void *context, const void *ptr)
 	talloc_set_destructor(handle, talloc_reference_destructor);
 	handle->ptr = discard_const_p(void, ptr);
 	_TLIST_ADD(tc->refs, handle);
+	handle->sticky = sticky;
 	return handle->ptr;
 }
 
+void *_talloc_reference(const void *context, const void *ptr)
+{
+	return __talloc_reference(context, ptr, false);
+}
+
+void *_talloc_reference_sticky(const void *context, const void *ptr)
+{
+	return __talloc_reference(context, ptr, false);
+}
 
 /* 
    internal talloc_free call
diff --git a/lib/talloc/talloc.h b/lib/talloc/talloc.h
index a4b33c3..8150cea 100644
--- a/lib/talloc/talloc.h
+++ b/lib/talloc/talloc.h
@@ -78,6 +78,7 @@ typedef void TALLOC_CTX;
 #endif
 
 #define talloc_reference(ctx, ptr) (_TALLOC_TYPEOF(ptr))_talloc_reference((ctx),(ptr))
+#define talloc_reference_sticky(ctx, ptr) (_TALLOC_TYPEOF(ptr))_talloc_reference_sticky((ctx),(ptr))
 #define talloc_move(ctx, ptr) (_TALLOC_TYPEOF(*(ptr)))_talloc_move((ctx),(void *)(ptr))
 
 /* useful macros for creating type checked pointers */
@@ -123,6 +124,7 @@ void *_talloc(const void *context, size_t size);
 void *talloc_pool(const void *context, size_t size);
 void _talloc_set_destructor(const void *ptr, int (*_destructor)(void *));
 int talloc_increase_ref_count(const void *ptr);
+int talloc_increase_ref_count_sticky(const void *ptr);
 size_t talloc_reference_count(const void *ptr);
 void *_talloc_reference(const void *context, const void *ptr);
 int talloc_unlink(const void *context, void *ptr);
-- 
1.6.0.3


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