From 3f8f71e23d6a453c969c0a0dbd764b9e19ef4f4b Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horiguchi.kyotaro@lab.ntt.co.jp>
Date: Thu, 18 Apr 2019 15:50:51 +0900
Subject: [PATCH 08/10] Make pg_waldump not use callback but call the function
 directly

This patch does the similar thing to the change in logical rep. Moves
callback from XLogReaderState from the parameter of
XLogFindNextRecord. Then invalidate the parameters callback and
private for XLogReaderAllocate.
---
 src/backend/access/transam/xlogreader.c | 17 +++++++----------
 src/bin/pg_waldump/pg_waldump.c         | 21 +++++++++------------
 src/include/access/xlogreader.h         | 14 +++++---------
 3 files changed, 21 insertions(+), 31 deletions(-)

diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c
index f953924a72..9b38fc7829 100644
--- a/src/backend/access/transam/xlogreader.c
+++ b/src/backend/access/transam/xlogreader.c
@@ -996,7 +996,8 @@ XLogReaderValidatePageHeader(XLogReaderState *state, XLogRecPtr recptr,
  * debugging purposes.
  */
 XLogRecPtr
-XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr)
+XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr,
+				   XLogFindNextRecordCB read_page, void *private)
 {
 	XLogReaderState saved_state = *state;
 	XLogRecPtr	tmpRecPtr;
@@ -1008,6 +1009,8 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr)
 
 	Assert(!XLogRecPtrIsInvalid(RecPtr));
 
+	XLREAD_RESET(state);
+
 	/*
 	 * skip over potential continuation data, keeping in mind that it may span
 	 * multiple pages
@@ -1035,9 +1038,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr)
 
 		/* Read the page containing the record */
 		while(XLogNeedData(state, targetPagePtr, targetRecOff))
-			state->read_page(state, state->loadPagePtr, state->loadLen,
-							 state->currRecPtr, state->readBuf,
-							 &state->readPageTLI);
+			read_page(state, private);
 
 		if (state->readLen < 0)
 			goto err;
@@ -1048,9 +1049,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr)
 
 		/* make sure we have enough data for the page header */
 		while (XLogNeedData(state, targetPagePtr, pageHeaderSize))
-			state->read_page(state, state->loadPagePtr, state->loadLen,
-							 state->currRecPtr, state->readBuf,
-							 &state->readPageTLI);
+			read_page(state, private);
 
 		if (state->readLen < 0)
 			goto err;
@@ -1097,9 +1096,7 @@ XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr)
 	{
 		if (result == XLREAD_NEED_DATA)
 		{
-			state->read_page(state, state->loadPagePtr, state->loadLen,
-							 state->currRecPtr,	state->readBuf,
-							 &state->readPageTLI);
+			read_page(state, private);
 			continue;
 		}
 
diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c
index acee7ae199..1966da493f 100644
--- a/src/bin/pg_waldump/pg_waldump.c
+++ b/src/bin/pg_waldump/pg_waldump.c
@@ -422,10 +422,12 @@ XLogDumpXLogRead(const char *directory, TimeLineID timeline_id,
  * XLogReader read_page callback
  */
 static void
-XLogDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen,
-				 XLogRecPtr targetPtr, char *readBuff, TimeLineID *curFileTLI)
+XLogDumpReadPage(XLogReaderState *state, void *priv)
 {
-	XLogDumpPrivate *private = state->private_data;
+	XLogRecPtr	targetPagePtr = state->loadPagePtr;
+	int			reqLen		  = state->loadLen;
+	char	   *readBuff	  = state->readBuf;
+	XLogDumpPrivate *private  = (XLogDumpPrivate *) priv;
 	int			count = XLOG_BLCKSZ;
 
 	if (private->endptr != InvalidXLogRecPtr)
@@ -1095,13 +1097,13 @@ main(int argc, char **argv)
 	/* done with argument parsing, do the actual work */
 
 	/* we have everything we need, start reading */
-	xlogreader_state = XLogReaderAllocate(WalSegSz, XLogDumpReadPage,
-										  &private);
+	xlogreader_state = XLogReaderAllocate(WalSegSz, NULL, NULL);
 	if (!xlogreader_state)
 		fatal_error("out of memory");
 
 	/* first find a valid recptr to start from */
-	first_record = XLogFindNextRecord(xlogreader_state, private.startptr);
+	first_record = XLogFindNextRecord(xlogreader_state, private.startptr,
+									  &XLogDumpReadPage, (void*) &private);
 
 	if (first_record == InvalidXLogRecPtr)
 		fatal_error("could not find a valid record after %X/%X",
@@ -1128,12 +1130,7 @@ main(int argc, char **argv)
 		while (XLogReadRecord(xlogreader_state,
 							  first_record, &record, &errormsg) ==
 			   XLREAD_NEED_DATA)
-			xlogreader_state->read_page(xlogreader_state,
-										xlogreader_state->loadPagePtr,
-										xlogreader_state->loadLen,
-										xlogreader_state->currRecPtr,
-										xlogreader_state->readBuf,
-										&xlogreader_state->readPageTLI);
+			XLogDumpReadPage(xlogreader_state, (void *) &private);
 
 		if (!record)
 		{
diff --git a/src/include/access/xlogreader.h b/src/include/access/xlogreader.h
index 9bfa9e8d54..b231cb330c 100644
--- a/src/include/access/xlogreader.h
+++ b/src/include/access/xlogreader.h
@@ -29,14 +29,6 @@
 
 typedef struct XLogReaderState XLogReaderState;
 
-/* Function type definition for the read_page callback */
-typedef void (*XLogPageReadCB) (XLogReaderState *xlogreader,
-							   XLogRecPtr targetPagePtr,
-							   int reqLen,
-							   XLogRecPtr targetRecPtr,
-							   char *readBuf,
-							   TimeLineID *pageTLI);
-
 typedef struct
 {
 	/* Is this block ref in use? */
@@ -263,7 +255,11 @@ extern bool XLogReaderValidatePageHeader(XLogReaderState *state,
 extern void XLogReaderInvalReadState(XLogReaderState *state);
 
 #ifdef FRONTEND
-extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr);
+/* Function type definition for the read_page callback */
+typedef void (*XLogFindNextRecordCB) (XLogReaderState *xlogreader,
+									  void *private);
+extern XLogRecPtr XLogFindNextRecord(XLogReaderState *state, XLogRecPtr RecPtr,
+									 XLogFindNextRecordCB read_page, void *private);
 #endif							/* FRONTEND */
 
 /* Functions for decoding an XLogRecord */
-- 
2.16.3

