move SK_MMAP_SUPPORT into SkPreConfig, so we can know about its availability

trunk/src/core/SkMMapStream.cpp

-
-/*
- * Copyright 2011 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-#include "SkMMapStream.h"
-
-#include <unistd.h>
-#include <sys/mman.h>
-#include <fcntl.h>
-#include <errno.h>
-
-SkMMAPStream::SkMMAPStream(const char filename[])
-{
-    fAddr = NULL;   // initialize to failure case
-    fSize = 0;
-
-    int fildes = open(filename, O_RDONLY);
-    if (fildes < 0)
-    {
-        SkDEBUGF(("---- failed to open(%s) for mmap stream error=%d\n", filename, errno));
-        return;
-    }
-
-    off_t offset = lseek(fildes, 0, SEEK_END);    // find the file size
-    if (offset == -1)
-    {
-        SkDEBUGF(("---- failed to lseek(%s) for mmap stream error=%d\n", filename, errno));
-        close(fildes);
-        return;
-    }
-    (void)lseek(fildes, 0, SEEK_SET);   // restore file offset to beginning
-
-    // to avoid a 64bit->32bit warning, I explicitly create a size_t size
-    size_t size = static_cast<size_t>(offset);
-
-    void* addr = mmap(NULL, size, PROT_READ, MAP_SHARED, fildes, 0);
-
-    // According to the POSIX documentation of mmap it adds an extra reference
-    // to the file associated with the fildes which is not removed by a
-    // subsequent close() on that fildes. This reference is removed when there
-    // are no more mappings to the file.
-    close(fildes);
-
-    if (MAP_FAILED == addr)
-    {
-        SkDEBUGF(("---- failed to mmap(%s) for mmap stream error=%d\n", filename, errno));
-        return;
-    }
-
-    this->INHERITED::setMemory(addr, size);
-
-    fAddr = addr;
-    fSize = size;
-}
-
-SkMMAPStream::~SkMMAPStream()
-{
-    this->closeMMap();
-}
-
-void SkMMAPStream::setMemory(const void* data, size_t length, bool copyData)
-{
-    this->closeMMap();
-    this->INHERITED::setMemory(data, length, copyData);
-}
-
-void SkMMAPStream::closeMMap()
-{
-    if (fAddr)
-    {
-        munmap(fAddr, fSize);
-        fAddr = NULL;
-    }
-}