Improve API of GenericXLogRegister().

Rename this function to GenericXLogRegisterBuffer() to make it clearer
what it does, and leave room for other sorts of "register" actions in
future.  Also, replace its "bool isNew" argument with an integer flags
argument, so as to allow adding more flags in future without an API
break.

Alexander Korotkov, adjusted slightly by me

2 files changed, 11 insertions, 6 deletions

diff --git a/src/backend/access/transam/generic_xlog.c b/src/backend/access/transam/generic_xlog.c
index e07bd836d2e..87a4861cddb 100644
--- a/src/backend/access/transam/generic_xlog.c
+++ b/src/backend/access/transam/generic_xlog.c
@@ -50,7 +50,7 @@
 typedef struct
 {
 	Buffer		buffer;			/* registered buffer */
-	bool		fullImage;		/* are we taking a full image of this page? */
+	int			flags;			/* flags for this buffer */
 	int			deltaLen;		/* space consumed in delta field */
 	char		image[BLCKSZ];	/* copy of page image for modification */
 	char		delta[MAX_DELTA_SIZE];	/* delta between page images */
@@ -280,9 +280,11 @@ GenericXLogStart(Relation relation)
  * is what the caller should modify.
  *
  * If the buffer is already registered, just return its existing entry.
+ * (It's not very clear what to do with the flags in such a case, but
+ * for now we stay with the original flags.)
  */
 Page
-GenericXLogRegister(GenericXLogState *state, Buffer buffer, bool isNew)
+GenericXLogRegisterBuffer(GenericXLogState *state, Buffer buffer, int flags)
 {
 	int			block_id;
 
@@ -295,7 +297,7 @@ GenericXLogRegister(GenericXLogState *state, Buffer buffer, bool isNew)
 		{
 			/* Empty slot, so use it (there cannot be a match later) */
 			page->buffer = buffer;
-			page->fullImage = isNew;
+			page->flags = flags;
 			memcpy(page->image,
 				   BufferGetPage(buffer, NULL, NULL, BGP_NO_SNAPSHOT_TEST),
 				   BLCKSZ);
@@ -347,7 +349,7 @@ GenericXLogFinish(GenericXLogState *state)
 								 BGP_NO_SNAPSHOT_TEST);
 			pageHeader = (PageHeader) pageData->image;
 
-			if (pageData->fullImage)
+			if (pageData->flags & GENERIC_XLOG_FULL_IMAGE)
 			{
 				/*
 				 * A full-page image does not require us to supply any xlog
diff --git a/src/include/access/generic_xlog.h b/src/include/access/generic_xlog.h
index 01743e38ff4..63f21206338 100644
--- a/src/include/access/generic_xlog.h
+++ b/src/include/access/generic_xlog.h
@@ -22,14 +22,17 @@
 
 #define MAX_GENERIC_XLOG_PAGES	XLR_NORMAL_MAX_BLOCK_ID
 
+/* Flag bits for GenericXLogRegisterBuffer */
+#define GENERIC_XLOG_FULL_IMAGE 0x0001	/* write full-page image */
+
 /* state of generic xlog record construction */
 struct GenericXLogState;
 typedef struct GenericXLogState GenericXLogState;
 
 /* API for construction of generic xlog records */
 extern GenericXLogState *GenericXLogStart(Relation relation);
-extern Page GenericXLogRegister(GenericXLogState *state, Buffer buffer,
-					bool isNew);
+extern Page GenericXLogRegisterBuffer(GenericXLogState *state, Buffer buffer,
+						  int flags);
 extern XLogRecPtr GenericXLogFinish(GenericXLogState *state);
 extern void GenericXLogAbort(GenericXLogState *state);