svn commit: r983398 - in /subversion/branches/performance/subversion: include/private/svn_temp_serializer.h libsvn_subr/svn_temp_serializer.c

[st...@apache.org]

Author: stefan2
Date: Sun Aug  8 12:20:40 2010
New Revision: 983398

URL: http://svn.apache.org/viewvc?rev=983398&view=rev
Log:
Simplify serialization of structures that may be a root structure as well
as being embedded into others. So, no longer require the initialization
routine to be provided with a root structure.

* subversion/libsvn_subr/svn_temp_serializer.c
  (svn_temp_serializer__init): don't try to store the root struct if none was given
  (store_current_end_pointer): don't try to update the parent reference, if there is none
* subversion/include/private/svn_temp_serializer.h
  (svn_temp_serializer__init, svn_temp_serializer__push, 
   svn_temp_serializer__add_string): explain the new options

Modified:
    subversion/branches/performance/subversion/include/private/svn_temp_serializer.h
    subversion/branches/performance/subversion/libsvn_subr/svn_temp_serializer.c

Modified: subversion/branches/performance/subversion/include/private/svn_temp_serializer.h
URL: http://svn.apache.org/viewvc/subversion/branches/performance/subversion/include/private/svn_temp_serializer.h?rev=983398&r1=983397&r2=983398&view=diff
==============================================================================
--- subversion/branches/performance/subversion/include/private/svn_temp_serializer.h (original)
+++ subversion/branches/performance/subversion/include/private/svn_temp_serializer.h Sun Aug  8 12:20:40 2010
@@ -46,6 +46,12 @@ typedef struct svn_temp_serializer__cont
  * of the actual structure. Due to the generic nature of the init function
  * we can't determine the structure size as part of the function.
  *
+ * It is possible to specify a @c NULL source_struct in which case the first
+ * call to @ref svn_temp_serializer__push will provide the root struct.
+ * Alternatively, one may even call @ref svn_temp_serializer__add_string
+ * but there is generally no point in doing so because the result will be
+ * simple string object in a @ref svn_stringbuf_t.
+ *
  * You may suggest a larger initial buffer size in @a suggested_buffer_size
  * to minimize the number of internal buffer re-allocations during the
  * serialization process. All allocations will be made from @a pool.
@@ -70,6 +76,11 @@ svn_temp_serializer__init(const void *so
  * the serialized structure can be established. @a struct_size must match
  * the result of @c sizeof() of the actual structure.
  *
+ * Only in case that @ref svn_temp_serializer__init has not been provided
+ * with a root structure and this is the first call after the initialization,
+ * @a source_struct will point to a reference to the root structure instead
+ * of being related to some other. 
+ *
  * Sub-structures and strings will be added in a FIFO fashion. If you need
  * add further sub-structures on the same level, you need to call @ref
  * svn_serializer__pop to realign the serialization context.
@@ -95,6 +106,10 @@ svn_temp_serializer__pop(svn_temp_serial
  * serialization @a context. @a s must be a reference to the @c char*
  * pointer in the original structure so that the correspondence in the
  * serialized structure can be established.
+ *
+ * Only in case that @ref svn_temp_serializer__init has not been provided
+ * with a root structure and this is the first call after the initialization,
+ * @a s will not be related to some struct.
  */
 void
 svn_temp_serializer__add_string(svn_temp_serializer__context_t *context,

Modified: subversion/branches/performance/subversion/libsvn_subr/svn_temp_serializer.c
URL: http://svn.apache.org/viewvc/subversion/branches/performance/subversion/libsvn_subr/svn_temp_serializer.c?rev=983398&r1=983397&r2=983398&view=diff
==============================================================================
--- subversion/branches/performance/subversion/libsvn_subr/svn_temp_serializer.c (original)
+++ subversion/branches/performance/subversion/libsvn_subr/svn_temp_serializer.c Sun Aug  8 12:20:40 2010
@@ -106,18 +106,28 @@ svn_temp_serializer__init(const void *so
                        ? struct_size
                        : suggested_buffer_size;
 
-  /* create the serialization context and initialize it, including the
-   * structure stack */
+  /* create the serialization context and initialize it */
   svn_temp_serializer__context_t *context = apr_palloc(pool, sizeof(*context));
   context->pool = pool;
   context->buffer = svn_stringbuf_create_ensure(init_size, pool);
-  context->source = apr_palloc(pool, sizeof(*context->source));
-  context->source->source_struct = source_struct;
-  context->source->target_offset = 0;
-  context->source->upper = NULL;
 
-  /* serialize, i.e. append, the content of the first structure */
-  svn_stringbuf_appendbytes(context->buffer, source_struct, struct_size);
+  /* If a source struct has been given, make it the root struct. */
+  if (source_struct)
+    {
+      context->source = apr_palloc(pool, sizeof(*context->source));
+      context->source->source_struct = source_struct;
+      context->source->target_offset = 0;
+      context->source->upper = NULL;
+
+      /* serialize, i.e. append, the content of the first structure */
+      svn_stringbuf_appendbytes(context->buffer, source_struct, struct_size);
+    }
+    else
+    {
+      /* The root struct will be set with the first push() op, or not at all
+       * (in case of a plain string). */
+      context->source = NULL;
+    }
 
   /* done */
   return context;
@@ -131,10 +141,17 @@ static void
 store_current_end_pointer(svn_temp_serializer__context_t *context,
                           const void * const * source_pointer)
 {
+  apr_size_t offset;
+  
+  /* if *source_pointer is the root struct, there will be no parent structure
+   * to relate it to */
+  if (context->source == NULL)
+    return;
+
   /* relative position of the serialized pointer to the begin of the buffer */
-  apr_size_t offset = (const char *)source_pointer
-                    - (const char *)context->source->source_struct
-                    + context->source->target_offset;
+  offset = (const char *)source_pointer
+         - (const char *)context->source->source_struct
+         + context->source->target_offset;
 
   /* use the serialized pointer as a storage for the offset */
   apr_size_t *target_string_ptr = (apr_size_t*)(context->buffer->data + offset);