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d5425d10ca
On Windows, we have to emulate the fstat() call to fill out information that takes extra effort to obtain, such as the file permissions/type. If all we want is the file size, we can use the much cheaper GetFileSizeEx() function (available since Windows XP). Suggested by Philip Kelley. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
46 lines
1.1 KiB
C
46 lines
1.1 KiB
C
#include "../git-compat-util.h"
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void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset)
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{
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HANDLE osfhandle, hmap;
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void *temp;
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LARGE_INTEGER len;
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uint64_t o = offset;
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uint32_t l = o & 0xFFFFFFFF;
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uint32_t h = (o >> 32) & 0xFFFFFFFF;
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osfhandle = (HANDLE)_get_osfhandle(fd);
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if (!GetFileSizeEx(osfhandle, &len))
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die("mmap: could not determine filesize");
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if ((length + offset) > len.QuadPart)
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length = xsize_t(len.QuadPart - offset);
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if (!(flags & MAP_PRIVATE))
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die("Invalid usage of mmap when built with USE_WIN32_MMAP");
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hmap = CreateFileMapping(osfhandle, NULL,
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prot == PROT_READ ? PAGE_READONLY : PAGE_WRITECOPY, 0, 0, NULL);
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if (!hmap) {
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errno = EINVAL;
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return MAP_FAILED;
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}
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temp = MapViewOfFileEx(hmap, prot == PROT_READ ?
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FILE_MAP_READ : FILE_MAP_COPY, h, l, length, start);
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if (!CloseHandle(hmap))
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warning("unable to close file mapping handle");
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if (temp)
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return temp;
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errno = GetLastError() == ERROR_COMMITMENT_LIMIT ? EFBIG : EINVAL;
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return MAP_FAILED;
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}
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int git_munmap(void *start, size_t length)
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{
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return !UnmapViewOfFile(start);
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}
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