modules/libreg/src/mmapio.c

   1 /* ***** BEGIN LICENSE BLOCK *****
   2  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   3  *
   4  * The contents of this file are subject to the Mozilla Public License Version
   5  * 1.1 (the "License"); you may not use this file except in compliance with
   6  * the License. You may obtain a copy of the License at
   7  * http://www.mozilla.org/MPL/
   8  *
   9  * Software distributed under the License is distributed on an "AS IS" basis,
  10  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  11  * for the specific language governing rights and limitations under the
  12  * License.
  13  *
  14  * The Original Code is Mozilla Communicator.
  15  *
  16  * The Initial Developer of the Original Code is
  17  * James L. Nance.
  18  * Portions created by the Initial Developer are Copyright (C) 1999
  19  * the Initial Developer. All Rights Reserved.
  20  *
  21  * Contributor(s):
  22  *   James L. Nance <jim_nance@yahoo.com>
  23  *
  24  * Alternatively, the contents of this file may be used under the terms of
  25  * either the GNU General Public License Version 2 or later (the "GPL"), or
  26  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  27  * in which case the provisions of the GPL or the LGPL are applicable instead
  28  * of those above. If you wish to allow use of your version of this file only
  29  * under the terms of either the GPL or the LGPL, and not to allow others to
  30  * use your version of this file under the terms of the MPL, indicate your
  31  * decision by deleting the provisions above and replace them with the notice
  32  * and other provisions required by the GPL or the LGPL. If you do not delete
  33  * the provisions above, a recipient may use your version of this file under
  34  * the terms of any one of the MPL, the GPL or the LGPL.
  35  *
  36  * ***** END LICENSE BLOCK ***** */
  37 #include <string.h>
  38 #include "mmapio.h"
  39 #include "prmem.h"
  40 #include "prlog.h"
  41
  42 struct MmioFileStruct
  43 {
  44     PRFileDesc *fd;
  45     PRFileMap  *fileMap;
  46     PRUint32   fsize; /* The size of the file */
  47     PRUint32   msize; /* The size of the mmap()ed area */
  48     PRInt32    pos;   /* Our logical position for doing I/O */
  49     char       *addr; /* The base address of our mapping */
  50     PRBool     needSeek; /* Do we need to seek to pos before doing a write() */
  51 };
  52
  53 PRStatus mmio_FileSeek(MmioFile *mmio, PRInt32 offset, PRSeekWhence whence)
  54 {
  55     mmio->needSeek = PR_TRUE;
  56
  57     switch(whence) {
  58         case PR_SEEK_SET:
  59             mmio->pos = offset;
  60             break;
  61         case PR_SEEK_END:
  62             mmio->pos = mmio->fsize + offset;
  63             break;
  64         case PR_SEEK_CUR:
  65             mmio->pos = mmio->pos + offset;
  66             break;
  67         default:
  68             return PR_FAILURE;
  69     }
  70
  71     if(mmio->pos<0) {
  72         mmio->pos = 0;
  73     }
  74
  75     return PR_SUCCESS;
  76 }
  77
  78 PRInt32  mmio_FileRead(MmioFile *mmio, char *dest, PRInt32 count)
  79 {
  80     static PRFileMapProtect prot = PR_PROT_READONLY;
  81     static PRInt64 fsize_l;
  82
  83     /* First see if we are going to try and read past the end of the file
  84      * and shorten count if we are.
  85     */
  86     if(mmio->pos+count > mmio->fsize) {
  87         count = mmio->fsize - mmio->pos;
  88     }
  89
  90     if(count<1) {
  91         return 0;
  92     }
  93
  94     /* Check to see if we need to remap for this read */
  95     if(mmio->pos+count > mmio->msize) {
  96         if(mmio->addr && mmio->msize) {
  97             PR_ASSERT(mmio->fileMap);
  98             PR_MemUnmap(mmio->addr, mmio->msize);
  99             PR_CloseFileMap(mmio->fileMap);
 100             mmio->addr  = NULL;
 101             mmio->msize = 0;
 102         }
 103
 104         LL_UI2L(fsize_l, mmio->fsize);
 105         mmio->fileMap = PR_CreateFileMap(mmio->fd, fsize_l, prot);
 106
 107         if(!mmio->fileMap) {
 108             return -1;
 109         }
 110
 111         mmio->addr = PR_MemMap(mmio->fileMap, 0, fsize_l);
 112
 113         if(!mmio->addr) {
 114             return -1;
 115         }
 116
 117         mmio->msize = mmio->fsize;
 118     }
 119
 120     memcpy(dest, mmio->addr+mmio->pos, count);
 121
 122     mmio->pos += count;
 123     mmio->needSeek = PR_TRUE;
 124
 125     return count;
 126 }
 127
 128 PRInt32  mmio_FileWrite(MmioFile *mmio, const char *src, PRInt32 count)
 129 {
 130     PRInt32 wcode;
 131
 132     if(mmio->needSeek) {
 133         PR_Seek(mmio->fd, mmio->pos, PR_SEEK_SET);
 134         mmio->needSeek = PR_FALSE;
 135     }
 136
 137     /* If this system does not keep mmap() and write() synchronized, we can
 138     ** force it to by doing an munmap() when we do a write.  This will
 139     ** obviously slow things down but fortunatly we do not do that many
 140     ** writes from within mozilla.  Platforms which need this may want to
 141     ** use the new USE_BUFFERED_REGISTRY_IO code instead of this code though.
 142     */
 143 #if MMAP_MISSES_WRITES
 144     if(mmio->addr && mmio->msize) {
 145         PR_ASSERT(mmio->fileMap);
 146         PR_MemUnmap(mmio->addr, mmio->msize);
 147         PR_CloseFileMap(mmio->fileMap);
 148         mmio->addr  = NULL;
 149         mmio->msize = 0;
 150     }
 151 #endif
 152
 153     wcode = PR_Write(mmio->fd, src, count);
 154
 155     if(wcode>0) {
 156         mmio->pos += wcode;
 157         if(mmio->pos>mmio->fsize) {
 158             mmio->fsize=mmio->pos;
 159         }
 160     }
 161
 162     return wcode;
 163 }
 164
 165 PRInt32  mmio_FileTell(MmioFile *mmio)
 166 {
 167     return mmio->pos;
 168 }
 169
 170 PRStatus mmio_FileClose(MmioFile *mmio)
 171 {
 172     if(mmio->addr && mmio->msize) {
 173         PR_ASSERT(mmio->fileMap);
 174         PR_MemUnmap(mmio->addr, mmio->msize);
 175         PR_CloseFileMap(mmio->fileMap);
 176     }
 177
 178     PR_Close(mmio->fd);
 179
 180     memset(mmio, 0, sizeof(*mmio)); /* Catch people who try to keep using it */
 181
 182     PR_Free(mmio);
 183
 184     return PR_SUCCESS;
 185 }
 186
 187 MmioFile *mmio_FileOpen(char *path, PRIntn flags, PRIntn mode)
 188 {
 189     PRFileDesc *fd = PR_Open(path, flags, mode);
 190     PRFileInfo info;
 191     MmioFile   *mmio;
 192
 193     if(!fd) {
 194         return NULL;
 195     }
 196
 197     mmio = PR_MALLOC(sizeof(MmioFile));
 198
 199     if(!mmio || PR_FAILURE==PR_GetOpenFileInfo(fd, &info)) {
 200         PR_Close(fd);
 201         return NULL;
 202     }
 203
 204     mmio->fd = fd;
 205     mmio->fileMap = NULL;
 206     mmio->fsize = info.size;
 207     mmio->msize = 0;
 208     mmio->pos   = 0;
 209     mmio->addr  = NULL;
 210     mmio->needSeek = PR_FALSE;
 211
 212     return mmio;
 213 }