Add comments to the changes of check-in (3200). (CVS 3202)

FossilOrigin-Name: 697498d4e86a42d7063417a9549ad04aaf4db31c

manifest

@@ -1,5 +1,5 @@
-C Fix\sa\swindows\sportability\sproblem\sin\strans.test.\s(CVS\s3201)
+C Add\scomments\sto\sthe\schanges\sof\scheck-in\s(3200).\s(CVS\s3202)
-D 2006-06-04T23:20:10
+D 2006-06-04T23:31:49
 F Makefile.in 87b6d483513ab8a4e763775bc5b434d6b5c34963
 F Makefile.linux-gcc 74ba0eadf88748a9ce3fd03d2a3ede2e6715baec
 F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
@@ -59,7 +59,7 @@ F src/os_test.c 49833426101f99aee4bb5f6a44b7c4b2029fda1c
 F src/os_test.h 903c93554c23d88f34f667f1979e4a1cee792af3
 F src/os_unix.c 17d91581a0ab478a06cb6f257b707a4c4a93e5a7
 F src/os_unix.h 5768d56d28240d3fe4537fac08cc85e4fb52279e
-F src/os_win.c e64e6bdfc42d867fff05f4d7a64ea110d675bcee
+F src/os_win.c c6976ae50b61fb5b7dce399e578aa1865f02b84f
 F src/os_win.h 41a946bea10f61c158ce8645e7646b29d44f122b
 F src/pager.c ddd05666bb89808a516baef2c186d6a75887ae90
 F src/pager.h 43f32f3847421f7502cfbb66f4eb2302b8033818
@@ -358,7 +358,7 @@ F www/tclsqlite.tcl bb0d1357328a42b1993d78573e587c6dcbc964b9
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
 F www/whentouse.tcl 97e2b5cd296f7d8057e11f44427dea8a4c2db513
-P f32dbe47ffd1e7e5695f02bf4263d80bea177ffb
+P f2538dfdb608b7f849bfc5fac0ec9d0d8dece4c7
-R fdbddefcc4faca3a136fc36ee74f50cf
+R 450ca953aa563fb633123fb7704167a9
 U drh
-Z 3232c1640de3ece87648ffe1a2cfee85
+Z 91538f76d1061379dfa3e8a2e60214bc

manifest.uuid

@@ -1 +1 @@
-f2538dfdb608b7f849bfc5fac0ec9d0d8dece4c7
+697498d4e86a42d7063417a9549ad04aaf4db31c

src/os_win.c

@@ -476,8 +476,18 @@ static BOOL winceLockFileEx(
 #endif /* OS_WINCE */
 
 /*
-** Delete the named file
+** Delete the named file.
+**
+** Note that windows does not allow a file to be deleted if some other
+** process has it open.  Sometimes a virus scanner or indexing program
+** will open a journal file shortly after it is created in order to do
+** whatever it is it does.  While this other process is holding the
+** file open, we will be unable to delete it.  To work around this
+** problem, we delay 100 milliseconds and try to delete again.  Up
+** to MX_DELETION_ATTEMPTs deletion attempts are run before giving
+** up and returning an error.
 */
+#define MX_DELETION_ATTEMPTS 3
 int sqlite3WinDelete(const char *zFilename){
   WCHAR *zWide = utf8ToUnicode(zFilename);
   int cnt = 0;
@@ -485,7 +495,7 @@ int sqlite3WinDelete(const char *zFilename){
   if( zWide ){
     do{
       rc = DeleteFileW(zWide);
-    }while( rc==0 && cnt++ < 3 && (Sleep(100), 1) );
+    }while( rc==0 && cnt++ < MX_DELETION_ATTEMPTS && (Sleep(100), 1) );
     sqliteFree(zWide);
   }else{
 #if OS_WINCE
@@ -493,7 +503,7 @@ int sqlite3WinDelete(const char *zFilename){
 #else
     do{
       rc = DeleteFileA(zFilename);
-    }while( rc==0 && cnt++ < 3 && (Sleep(100), 1) );
+    }while( rc==0 && cnt++ < MX_DELETION_ATTEMPTS && (Sleep(100), 1) );
 #endif
   }
   TRACE2("DELETE \"%s\"\n", zFilename);
@@ -630,6 +640,12 @@ int sqlite3WinOpenReadWrite(
 ** On success, write the file handle into *id and return SQLITE_OK.
 **
 ** On failure, return SQLITE_CANTOPEN.
+**
+** Sometimes if we have just deleted a prior journal file, windows
+** will fail to open a new one because there is a "pending delete".
+** To work around this bug, we pause for 100 milliseconds and attempt
+** a second open after the first one fails.  The whole operation only
+** fails if both open attempts are unsuccessful.
 */
 int sqlite3WinOpenExclusive(const char *zFilename, OsFile **pId, int delFlag){
   winFile f;
@@ -808,7 +824,15 @@ int sqlite3WinTempFileName(char *zBuf){
 
 /*
 ** Close a file.
+**
+** It is reported that an attempt to close a handle might sometimes
+** fail.  This is a very unreasonable result, but windows is notorious
+** for being unreasonable so I do not doubt that it might happen.  If
+** the close fails, we pause for 100 milliseconds and try again.  As
+** many as MX_CLOSE_ATTEMPT attempts to close the handle are made before
+** giving up and returning an error.
 */
+#define MX_CLOSE_ATTEMPT 3
 static int winClose(OsFile **pId){
   winFile *pFile;
   int rc = 1;
@@ -817,7 +841,7 @@ static int winClose(OsFile **pId){
     TRACE2("CLOSE %d\n", pFile->h);
     do{
       rc = CloseHandle(pFile->h);
-    }while( rc==0 && cnt++ < 3 && (Sleep(100), 1) );
+    }while( rc==0 && cnt++ < MX_CLOSE_ATTEMPT && (Sleep(100), 1) );
 #if OS_WINCE
     winceDestroyLock(pFile);
     if( pFile->zDeleteOnClose ){