Tidy up XLogSource code in xlog.c.

This commit replaces 0 used as an initial value of XLogSource variable,
with XLOG_FROM_ANY. Also this commit changes those variable so that
XLogSource instead of int is used as the type for them. These changes
are for code readability and debugger-friendliness.

Author: Kyotaro Horiguchi
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/20200227.124830.2197604521555566121.horikyota.ntt@gmail.com

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index b0e953f89482db7408c89aa709e5fea2faf3a52b..bffa94f36e4c01c41ba1c91fbdcc6aff24d7cdb9 100644 (file)
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -795,7 +795,7 @@ static int  readFile = -1;
 static XLogSegNo readSegNo = 0;
 static uint32 readOff = 0;
 static uint32 readLen = 0;
-static XLogSource readSource = 0;      /* XLOG_FROM_* code */
+static XLogSource readSource = XLOG_FROM_ANY;
 
 /*
  * Keeps track of which source we're currently reading from. This is
@@ -804,7 +804,7 @@ static XLogSource readSource = 0;   /* XLOG_FROM_* code */
  * attempt to read from currentSource failed, and we should try another source
  * next.
  */
-static XLogSource currentSource = 0;   /* XLOG_FROM_* code */
+static XLogSource currentSource = XLOG_FROM_ANY;
 static bool lastSourceFailed = false;
 
 typedef struct XLogPageReadPrivate
@@ -823,7 +823,7 @@ typedef struct XLogPageReadPrivate
  * XLogReceiptSource tracks where we last successfully read some WAL.)
  */
 static TimestampTz XLogReceiptTime = 0;
-static XLogSource XLogReceiptSource = 0;       /* XLOG_FROM_* code */
+static XLogSource XLogReceiptSource = XLOG_FROM_ANY;
 
 /* State information for XLOG reading */
 static XLogRecPtr ReadRecPtr;  /* start of last record read */
@@ -886,8 +886,8 @@ static bool InstallXLogFileSegment(XLogSegNo *segno, char *tmppath,
                                                                   bool find_free, XLogSegNo max_segno,
                                                                   bool use_lock);
 static int     XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli,
-                                                int source, bool notfoundOk);
-static int     XLogFileReadAnyTLI(XLogSegNo segno, int emode, int source);
+                                                XLogSource source, bool notfoundOk);
+static int     XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source);
 static int     XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr,
                                                 int reqLen, XLogRecPtr targetRecPtr, char *readBuf);
 static bool WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
@@ -3633,7 +3633,7 @@ XLogFileOpen(XLogSegNo segno)
  */
 static int
 XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli,
-                        int source, bool notfoundOk)
+                        XLogSource source, bool notfoundOk)
 {
        char            xlogfname[MAXFNAMELEN];
        char            activitymsg[MAXFNAMELEN + 16];
@@ -3715,7 +3715,7 @@ XLogFileRead(XLogSegNo segno, int emode, TimeLineID tli,
  * This version searches for the segment with any TLI listed in expectedTLEs.
  */
 static int
-XLogFileReadAnyTLI(XLogSegNo segno, int emode, int source)
+XLogFileReadAnyTLI(XLogSegNo segno, int emode, XLogSource source)
 {
        char            path[MAXPGPATH];
        ListCell   *cell;
@@ -4387,7 +4387,7 @@ ReadRecord(XLogReaderState *xlogreader, int emode,
                                 * so that we will check the archive next.
                                 */
                                lastSourceFailed = false;
-                               currentSource = 0;
+                               currentSource = XLOG_FROM_ANY;
 
                                continue;
                        }
@@ -11673,7 +11673,7 @@ XLogPageRead(XLogReaderState *xlogreader, XLogRecPtr targetPagePtr, int reqLen,
 
                close(readFile);
                readFile = -1;
-               readSource = 0;
+               readSource = XLOG_FROM_ANY;
        }
 
        XLByteToSeg(targetPagePtr, readSegNo, wal_segment_size);
@@ -11693,7 +11693,7 @@ retry:
                                close(readFile);
                        readFile = -1;
                        readLen = 0;
-                       readSource = 0;
+                       readSource = XLOG_FROM_ANY;
 
                        return -1;
                }
@@ -11799,7 +11799,7 @@ next_record_is_invalid:
                close(readFile);
        readFile = -1;
        readLen = 0;
-       readSource = 0;
+       readSource = XLOG_FROM_ANY;
 
        /* In standby-mode, keep trying */
        if (StandbyMode)
@@ -11870,7 +11870,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
         */
        if (!InArchiveRecovery)
                currentSource = XLOG_FROM_PG_WAL;
-       else if (currentSource == 0 ||
+       else if (currentSource == XLOG_FROM_ANY ||
                         (!StandbyMode && currentSource == XLOG_FROM_STREAM))
        {
                lastSourceFailed = false;
@@ -11879,7 +11879,7 @@ WaitForWALToBecomeAvailable(XLogRecPtr RecPtr, bool randAccess,
 
        for (;;)
        {
-               int                     oldSource = currentSource;
+               XLogSource      oldSource = currentSource;
 
                /*
                 * First check if we failed to read from the current source, and