mirror of
https://github.com/mozilla/gecko-dev.git
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97 lines
2.8 KiB
C++
97 lines
2.8 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#if defined(XP_UNIX)
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#include <fcntl.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#elif defined(XP_WIN)
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#include <windows.h>
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#elif defined(XP_OS2)
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#define INCL_DOSFILEMGR
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#include <os2.h>
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#endif
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#include "nscore.h"
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#include "private/pprio.h"
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#include "mozilla/FileUtils.h"
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bool
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mozilla::fallocate(PRFileDesc *aFD, int64_t aLength)
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{
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#if defined(HAVE_POSIX_FALLOCATE)
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return posix_fallocate(PR_FileDesc2NativeHandle(aFD), 0, aLength) == 0;
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#elif defined(XP_WIN)
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int64_t oldpos = PR_Seek64(aFD, 0, PR_SEEK_CUR);
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if (oldpos == -1)
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return false;
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if (PR_Seek64(aFD, aLength, PR_SEEK_SET) != aLength)
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return false;
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bool retval = (0 != SetEndOfFile((HANDLE)PR_FileDesc2NativeHandle(aFD)));
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PR_Seek64(aFD, oldpos, PR_SEEK_SET);
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return retval;
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#elif defined(XP_OS2)
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return aLength <= UINT32_MAX
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&& 0 == DosSetFileSize(PR_FileDesc2NativeHandle(aFD), (uint32_t)aLength);
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#elif defined(XP_MACOSX)
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int fd = PR_FileDesc2NativeHandle(aFD);
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fstore_t store = {F_ALLOCATECONTIG, F_PEOFPOSMODE, 0, aLength};
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// Try to get a continous chunk of disk space
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int ret = fcntl(fd, F_PREALLOCATE, &store);
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if (-1 == ret) {
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// OK, perhaps we are too fragmented, allocate non-continuous
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store.fst_flags = F_ALLOCATEALL;
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ret = fcntl(fd, F_PREALLOCATE, &store);
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if (-1 == ret)
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return false;
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}
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return 0 == ftruncate(fd, aLength);
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#elif defined(XP_UNIX)
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// The following is copied from fcntlSizeHint in sqlite
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/* If the OS does not have posix_fallocate(), fake it. First use
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** ftruncate() to set the file size, then write a single byte to
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** the last byte in each block within the extended region. This
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** is the same technique used by glibc to implement posix_fallocate()
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** on systems that do not have a real fallocate() system call.
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*/
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int64_t oldpos = PR_Seek64(aFD, 0, PR_SEEK_CUR);
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if (oldpos == -1)
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return false;
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struct stat buf;
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int fd = PR_FileDesc2NativeHandle(aFD);
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if (fstat(fd, &buf))
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return false;
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if (buf.st_size >= aLength)
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return false;
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const int nBlk = buf.st_blksize;
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if (!nBlk)
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return false;
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if (ftruncate(fd, aLength))
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return false;
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int nWrite; // Return value from write()
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int64_t iWrite = ((buf.st_size + 2 * nBlk - 1) / nBlk) * nBlk - 1; // Next offset to write to
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while (iWrite < aLength) {
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nWrite = 0;
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if (PR_Seek64(aFD, iWrite, PR_SEEK_SET) == iWrite)
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nWrite = PR_Write(aFD, "", 1);
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if (nWrite != 1) break;
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iWrite += nBlk;
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}
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PR_Seek64(aFD, oldpos, PR_SEEK_SET);
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return nWrite == 1;
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#endif
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return false;
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}
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