mmap portability layer, mmap for Windows

new macro: thread_safe_decrement, thread_safe_dec_and_test, statistic_decrement


mysys/my_chsize.c:
  cleanup
include/config-win.h:
  mmap portability layer, mmap for Windows
include/my_pthread.h:
  thread_safe_decrement, thread_safe_dec_and_test, statistic_decrement
include/my_sys.h:
  mmap portability layer, mmap for Windows
mysys/Makefile.am:
  mmap portability layer, mmap for Windows

include/config-win.h

@@ -301,6 +301,9 @@ inline double ulonglong2double(ulonglong value)
 #define HAVE_SETFILEPOINTER
 #define HAVE_VIO
 
+#define HAME_MMAP               /* in mysys/my_mmap.c */
+#define HAVE_GETPAGESIZE        /* in mysys/my_mmap.c */
+
 #ifdef NOT_USED
 #define HAVE_SNPRINTF		/* Gave link error */
 #define _snprintf snprintf

include/my_pthread.h

@@ -674,21 +674,43 @@ extern pthread_t shutdown_th, main_th, signal_th;
 
 #ifndef thread_safe_increment
 #ifdef HAVE_ATOMIC_ADD
-#define thread_safe_increment(V,L) atomic_add(1,(atomic_t*) &V);
+#define thread_safe_increment(V,L) atomic_inc((atomic_t*) &V);
+#define thread_safe_decrement(V,L) atomic_dec((atomic_t*) &V);
+#define thread_safe_dec_and_test(V, L) atomic_dec_and_test((atomic_t*) &V);
 #define thread_safe_add(V,C,L)     atomic_add((C),(atomic_t*) &V);
 #define thread_safe_sub(V,C,L)     atomic_sub((C),(atomic_t*) &V);
 #else
 #define thread_safe_increment(V,L) \
-	pthread_mutex_lock((L)); (V)++; pthread_mutex_unlock((L));
-#define thread_safe_add(V,C,L) \
-	pthread_mutex_lock((L)); (V)+=(C); pthread_mutex_unlock((L));
+        (pthread_mutex_lock((L)), (V)++, pthread_mutex_unlock((L)))
+#define thread_safe_decrement(V,L) \
+        (pthread_mutex_lock((L)), (V)--, pthread_mutex_unlock((L)))
+#define thread_safe_add(V,C,L) (pthread_mutex_lock((L)), (V)+=(C), pthread_mutex_unlock((L)))
 #define thread_safe_sub(V,C,L) \
-	pthread_mutex_lock((L)); (V)-=(C); pthread_mutex_unlock((L));
+        (pthread_mutex_lock((L)), (V)-=(C), pthread_mutex_unlock((L)))
+#if defined (__GNUC__) || defined (__cplusplus)
+static inline bool thread_safe_dec_and_test(ulong V, pthread_mutex_t *L)
+{
+  ulong res;
+  pthread_mutex_lock(L);
+  res=V--;
+  pthread_mutex_unlock(L);
+  return res==0;
+}
+#else
+/*
+  what should we do ? define it as static ?
+  a regular function somewhere in mysys/  ?
+  for now it's only used in c++ code, so there's no need to bother
+*/
+#warning "No thread_safe_dec_and_test() for this architecture"
+#endif
 #endif /* HAVE_ATOMIC_ADD */
 #ifdef SAFE_STATISTICS
 #define statistic_increment(V,L)   thread_safe_increment((V),(L))
+#define statistic_decrement(V,L)   thread_safe_decrement((V),(L))
 #define statistic_add(V,C,L)       thread_safe_add((V),(C),(L))
 #else
+#define statistic_decrement(V,L) (V)--
 #define statistic_increment(V,L) (V)++
 #define statistic_add(V,C,L)     (V)+=(C)
 #endif /* SAFE_STATISTICS */

include/my_sys.h

@@ -772,6 +772,32 @@ void my_free_open_file_info(void);
 ulonglong my_getsystime(void);
 my_bool my_gethwaddr(uchar *to);
 
+#ifdef HAVE_MMAP
+#include <sys/mman.h>
+
+#ifndef MAP_NOSYNC
+#define MAP_NOSYNC      0
+#endif
+
+#define my_mmap(a,b,c,d,e,f)    mmap(a,b,c,d,e,f)
+#define my_getpagesize()        getpagesize()
+#define my_munmap(a,b)          munmap(a,b)
+
+#else
+/* not a complete set of mmap() flags, but only those that nesessary */
+#define PROT_READ        1
+#define PROT_WRITE       2
+#define MAP_NOSYNC       0x800
+#define MAP_FAILED       ((void *)-1)
+#define MS_SYNC          0x0000
+
+int my_getpagesize(void);
+void *my_mmap(void *, size_t, int, int, int, my_off_t);
+int my_munmap(void *, size_t);
+#endif
+
+int my_msync(int, void *, size_t, int);
+
 /* character sets */
 extern uint get_charset_number(const char *cs_name, uint cs_flags);
 extern uint get_collation_number(const char *name);

mysys/Makefile.am

@@ -26,7 +26,7 @@ noinst_HEADERS =	mysys_priv.h my_static.h \
 			my_os2cond.c my_os2dirsrch.c my_os2dirsrch.h \
 			my_os2dlfcn.c my_os2file64.c my_os2mutex.c \
 			my_os2thread.c my_os2tls.c
-libmysys_a_SOURCES =	my_init.c my_getwd.c mf_getdate.c \
+libmysys_a_SOURCES =    my_init.c my_getwd.c mf_getdate.c my_mmap.c \
 			mf_path.c mf_loadpath.c my_file.c \
 			my_open.c my_create.c my_dup.c my_seek.c my_read.c \
 			my_pread.c my_write.c \

mysys/my_chsize.c

@@ -48,9 +48,9 @@ int my_chsize(File fd, my_off_t newlength, int filler, myf MyFlags)
   DBUG_PRINT("info",("old_size: %ld", (ulong) oldsize));
 
   if (oldsize > newlength)
+  {
 #if defined(HAVE_SETFILEPOINTER)
   /* This is for the moment only true on windows */
-  {
     long is_success;
     HANDLE win_file= (HANDLE) _get_osfhandle(fd);
     long length_low, length_high;
@@ -63,35 +63,29 @@ int my_chsize(File fd, my_off_t newlength, int filler, myf MyFlags)
       DBUG_RETURN(0);
     my_errno= GetLastError();
     goto err;
-  }
 #elif defined(HAVE_FTRUNCATE)
-  {
     if (ftruncate(fd, (off_t) newlength))
     {
       my_errno= errno;
       goto err;
     }
     DBUG_RETURN(0);
-  }
 #elif defined(HAVE_CHSIZE)
-  {
     if (chsize(fd, (off_t) newlength))
     {
       my_errno=errno;
       goto err;
     }
     DBUG_RETURN(0);
-  }
 #else
-  {
     /*
       Fill space between requested length and true length with 'filler'
       We should never come here on any modern machine
     */
     VOID(my_seek(fd, newlength, MY_SEEK_SET, MYF(MY_WME+MY_FAE)));
     swap_variables(my_off_t, newlength, oldsize);
-  }
 #endif
+  }
 
   /* Full file with 'filler' until it's as big as requested */
   bfill(buff, IO_SIZE, filler);

mysys/my_mmap.c

@@ -0,0 +1,89 @@
+/* Copyright (C) 2000-2003 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#include "mysys_priv.h"
+
+#ifdef HAVE_MMAP
+
+/*
+  system msync() only syncs mmap'ed area to fs cache.
+  fsync() is required to really sync to disc
+*/
+int my_msync(int fd, void *addr, size_t len, int flags)
+{
+  msync(addr, len, flags);
+  return my_sync(fd, MYF(0));
+}
+
+#else
+#ifdef __WIN__
+
+static SECURITY_ATTRIBUTES mmap_security_attributes=
+  {sizeof(SECURITY_ATTRIBUTES), 0, TRUE};
+
+int my_getpagesize(void)
+{
+  SYSTEM_INFO si;
+  GetSystemInfo(&si);
+  return si.dwPageSize;
+}
+
+void *my_mmap(void *addr, size_t len, int prot,
+               int flags, int fd, my_off_t offset)
+{
+  DWORD flProtect=0;
+  HANDLE hFileMap;
+  LPVOID ptr;
+
+  flProtect|=SEC_COMMIT;
+
+  hFileMap=CreateFileMapping(fd, NULL, &mmap_security_attributes,
+                             PAGE_READWRITE, 0, len, 0);
+  if (hFileMap == 0)
+    return MAP_FAILED;
+
+  ptr=MapViewOfFile(hFileMap,
+                    flags & PROT_WRITE ? FILE_MAP_WRITE : FILE_MAP_READ,
+                    (DWORD)(offset >> 32), (DWORD)offset, len);
+
+  /*
+    MSDN explicitly states that it's possible to close File Mapping Object
+    even when a view is not unmapped - then the object will be held open
+    implicitly until unmap, as every view stores internally a handler of
+    a corresponding File Mapping Object
+   */
+  CloseHandle(hFileMap);
+
+  if (ptr)
+    return ptr;
+
+  return MAP_FAILED;
+}
+
+int my_munmap(void *addr, size_t len)
+{
+  return UnmapViewOfFile(addr) ? 0 : -1;
+}
+
+int my_msync(int fd, void *addr, size_t len, int flags)
+{
+  return FlushViewOfFile(addr, len) ? 0 : -1;
+}
+
+#endif
+#error "no mmap!"
+#endif
+