This is the downport of

Bug#24509 - 2048 file descriptor limit on windows needs increasing, also 
WL#3049 - improved Windows I/O
                        
The patch replaces the use of the POSIX I/O interfaces in mysys on Windows with 
the Win32 API calls (CreateFile, WriteFile, etc). The Windows HANDLE for the open 
file is stored in the my_file_info struct, along with a flag for append mode 
because the Windows API does not support opening files in append mode in all cases)
The default max open files has been increased to 16384 and can be increased further
by setting --max-open-files=<value> during the server start.
                              
Another major change in this patch that almost all Windows specific file IO code
has been moved to a new file my_winfile.c, greatly reducing the amount of code 
in #ifdef blocks within mysys, thus improving readability.
                               
                                    
Minor enhancements:
- my_(f)stat() is changed to use __stati64 structure with  64 file size
and timestamps. It will return correct file size now (C runtime implementation
used to report outdated information)
- my_lock on Windows is prepared to handle additional timeout parameter
- after review : changed __WIN__ to _WIN32 in the new and changed code.

1 files changed, 61 insertions, 42 deletions

diff --git a/mysys/my_pread.c b/mysys/my_pread.c
index 3f62f150c91..eaabcb1b728 100644
--- a/mysys/my_pread.c
+++ b/mysys/my_pread.c
@@ -15,11 +15,15 @@
 
 #include "mysys_priv.h"
 #include "mysys_err.h"
+#include "my_base.h"
+#include <m_string.h>
 #include <errno.h>
-#ifdef HAVE_PREAD
+#if defined (HAVE_PREAD) && !defined(_WIN32)
 #include <unistd.h>
 #endif
 
+
+
 /*
   Read a chunk of bytes from a file from a given position
 
@@ -46,27 +50,39 @@ size_t my_pread(File Filedes, uchar *Buffer, size_t Count, my_off_t offset,
 {
   size_t readbytes;
   int error= 0;
+#if !defined (HAVE_PREAD) && !defined (_WIN32)
+  int save_errno;
+#endif
   DBUG_ENTER("my_pread");
-  DBUG_PRINT("my",("Fd: %d  Seek: %lu  Buffer: 0x%lx  Count: %u  MyFlags: %d",
-		   Filedes, (ulong) offset, (long) Buffer, (uint) Count,
-                   MyFlags));
+  DBUG_PRINT("my",("fd: %d  Seek: %llu  Buffer: %p  Count: %lu  MyFlags: %d",
+             Filedes, (ulonglong)offset, Buffer, (ulong)Count, MyFlags));
   for (;;)
   {
-#ifndef __WIN__
-    errno=0;					/* Linux doesn't reset this */
-#endif
-#ifndef HAVE_PREAD
+    errno= 0;    /* Linux, Windows don't reset this on EOF/success */
+#if !defined (HAVE_PREAD) && !defined (_WIN32)
     pthread_mutex_lock(&my_file_info[Filedes].mutex);
     readbytes= (uint) -1;
     error= (lseek(Filedes, offset, MY_SEEK_SET) == (my_off_t) -1 ||
-	    (readbytes= read(Filedes, Buffer, (uint) Count)) != Count);
+           (readbytes= read(Filedes, Buffer, Count)) != Count);
+    save_errno= errno;
     pthread_mutex_unlock(&my_file_info[Filedes].mutex);
+    if (error)
+      errno= save_errno;
 #else
-    if ((error= ((readbytes= pread(Filedes, Buffer, Count, offset)) != Count)))
-      my_errno= errno ? errno : -1;
+#if defined(_WIN32)
+    readbytes= my_win_pread(Filedes, Buffer, Count, offset);
+#else 
+    readbytes= pread(Filedes, Buffer, Count, offset);
+#endif
+    error= (readbytes != Count);
 #endif
-    if (error || readbytes != Count)
+    if(error)
     {
+      my_errno= errno ? errno : -1;
+      if (errno == 0 || (readbytes != (size_t) -1 &&
+                      (MyFlags & (MY_NABP | MY_FNABP))))
+         my_errno= HA_ERR_FILE_TOO_SHORT;
+
       DBUG_PRINT("warning",("Read only %d bytes off %u from %d, errno: %d",
                             (int) readbytes, (uint) Count,Filedes,my_errno));
 #ifdef THREAD
@@ -79,19 +95,19 @@ size_t my_pread(File Filedes, uchar *Buffer, size_t Count, my_off_t offset,
 #endif
       if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
       {
-	if (readbytes == (size_t) -1)
-	  my_error(EE_READ, MYF(ME_BELL+ME_WAITTANG),
-		   my_filename(Filedes),my_errno);
-	else if (MyFlags & (MY_NABP | MY_FNABP))
-	  my_error(EE_EOFERR, MYF(ME_BELL+ME_WAITTANG),
-		   my_filename(Filedes),my_errno);
+        if (readbytes == (size_t) -1)
+          my_error(EE_READ, MYF(ME_BELL+ME_WAITTANG),
+                   my_filename(Filedes),my_errno);
+        else if (MyFlags & (MY_NABP | MY_FNABP))
+          my_error(EE_EOFERR, MYF(ME_BELL+ME_WAITTANG),
+                   my_filename(Filedes),my_errno);
       }
       if (readbytes == (size_t) -1 || (MyFlags & (MY_FNABP | MY_NABP)))
-	DBUG_RETURN(MY_FILE_ERROR);		/* Return with error */
+        DBUG_RETURN(MY_FILE_ERROR);         /* Return with error */
     }
     if (MyFlags & (MY_NABP | MY_FNABP))
-      DBUG_RETURN(0);				/* Read went ok; Return 0 */
-    DBUG_RETURN(readbytes);			/* purecov: inspected */
+      DBUG_RETURN(0);                      /* Read went ok; Return 0 */
+    DBUG_RETURN(readbytes);                /* purecov: inspected */
   }
 } /* my_pread */
 
@@ -117,42 +133,45 @@ size_t my_pread(File Filedes, uchar *Buffer, size_t Count, my_off_t offset,
     #             Number of bytes read
 */
 
-size_t my_pwrite(int Filedes, const uchar *Buffer, size_t Count,
+size_t my_pwrite(File Filedes, const uchar *Buffer, size_t Count,
                  my_off_t offset, myf MyFlags)
 {
-  size_t writenbytes, written;
+  size_t writtenbytes, written;
   uint errors;
+
   DBUG_ENTER("my_pwrite");
-  DBUG_PRINT("my",("Fd: %d  Seek: %lu  Buffer: 0x%lx  Count: %u  MyFlags: %d",
-		   Filedes, (ulong) offset, (long) Buffer, (uint) Count,
-                   MyFlags));
+  DBUG_PRINT("my",("fd: %d  Seek: %llu  Buffer: %p  Count: %lu  MyFlags: %d",
+             Filedes, offset, Buffer, (ulong)Count, MyFlags));
   errors= 0;
   written= 0;
 
   for (;;)
   {
-#ifndef HAVE_PREAD
+#if !defined (HAVE_PREAD) && !defined (_WIN32)
     int error;
-    writenbytes= (size_t) -1;
+    writtenbytes= (size_t) -1;
     pthread_mutex_lock(&my_file_info[Filedes].mutex);
     error= (lseek(Filedes, offset, MY_SEEK_SET) != (my_off_t) -1 &&
-            (writenbytes = write(Filedes, Buffer, (uint) Count)) == Count);
+            (writtenbytes= write(Filedes, Buffer, Count)) == Count);
     pthread_mutex_unlock(&my_file_info[Filedes].mutex);
     if (error)
       break;
+#elif defined (_WIN32)
+    writtenbytes= my_win_pwrite(Filedes, Buffer, Count, offset);
 #else
-    if ((writenbytes= pwrite(Filedes, Buffer, Count,offset)) == Count)
+    writtenbytes= pwrite(Filedes, Buffer, Count, offset);
+#endif
+    if(writtenbytes == Count)
       break;
     my_errno= errno;
-#endif
-    if (writenbytes != (size_t) -1)
-    {					/* Safegueard */
-      written+=writenbytes;
-      Buffer+=writenbytes;
-      Count-=writenbytes;
-      offset+=writenbytes;
+    if (writtenbytes != (size_t) -1)
+    {
+      written+= writtenbytes;
+      Buffer+= writtenbytes;
+      Count-= writtenbytes;
+      offset+= writtenbytes;
     }
-    DBUG_PRINT("error",("Write only %u bytes", (uint) writenbytes));
+    DBUG_PRINT("error",("Write only %u bytes", (uint) writtenbytes));
 #ifndef NO_BACKGROUND
 #ifdef THREAD
     if (my_thread_var->abort)
@@ -165,15 +184,15 @@ size_t my_pwrite(int Filedes, const uchar *Buffer, size_t Count,
       errors++;
       continue;
     }
-    if ((writenbytes && writenbytes != (size_t) -1) || my_errno == EINTR)
+    if ((writtenbytes && writtenbytes != (size_t) -1) || my_errno == EINTR)
       continue;					/* Retry */
 #endif
     if (MyFlags & (MY_NABP | MY_FNABP))
     {
       if (MyFlags & (MY_WME | MY_FAE | MY_FNABP))
       {
-	my_error(EE_WRITE, MYF(ME_BELL | ME_WAITTANG),
-		 my_filename(Filedes),my_errno);
+        my_error(EE_WRITE, MYF(ME_BELL | ME_WAITTANG),
+                 my_filename(Filedes),my_errno);
       }
       DBUG_RETURN(MY_FILE_ERROR);		/* Error on read */
     }
@@ -183,5 +202,5 @@ size_t my_pwrite(int Filedes, const uchar *Buffer, size_t Count,
   DBUG_EXECUTE_IF("check", my_seek(Filedes, -1, SEEK_SET, MYF(0)););
   if (MyFlags & (MY_NABP | MY_FNABP))
     DBUG_RETURN(0);			/* Want only errors */
-  DBUG_RETURN(writenbytes+written); /* purecov: inspected */
+  DBUG_RETURN(writtenbytes+written); /* purecov: inspected */
 } /* my_pwrite */