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fix memfiles

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This commit is contained in:
narimiran
2023-02-18 10:50:33 +01:00
parent d070ccbc03
commit 6af6818fe9
1 changed files with 26 additions and 27 deletions
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53
lib/pure/memfiles.nim
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@@ -314,33 +314,32 @@ proc flush*(f: var MemFile; attempts: Natural = 3) =
if lastErr != EBUSY.OSErrorCode:
raiseOSError(lastErr, "error flushing mapping")
when defined(posix) or defined(nimdoc):
proc resize*(f: var MemFile, newFileSize: int) {.raises: [IOError, OSError].} =
## resize and re-map the file underlying an `allowRemap MemFile`.
## **Note**: this assumes the entire file is mapped read-write at offset zero.
## Also, the value of `.mem` will probably change.
## **Note**: This is not (yet) available on Windows.
when defined(posix):
if f.handle == -1:
raise newException(IOError,
"Cannot resize MemFile opened with allowRemap=false")
if ftruncate(f.handle, newFileSize) == -1:
raiseOSError(osLastError())
when defined(linux): #Maybe NetBSD, too?
#On Linux this can be over 100 times faster than a munmap,mmap cycle.
proc mremap(old: pointer; oldSize, newSize: csize; flags: cint):
pointer {.importc: "mremap", header: "<sys/mman.h>".}
let newAddr = mremap(f.mem, csize(f.size), csize(newFileSize), cint(1))
if newAddr == cast[pointer](MAP_FAILED):
raiseOSError(osLastError())
else:
if munmap(f.mem, f.size) != 0:
raiseOSError(osLastError())
let newAddr = mmap(nil, newFileSize, PROT_READ or PROT_WRITE,
f.flags, f.handle, 0)
if newAddr == cast[pointer](MAP_FAILED):
raiseOSError(osLastError())
f.mem = newAddr
proc resize*(f: var MemFile, newFileSize: int) {.raises: [IOError, OSError].} =
## Resize & re-map the file underlying an `allowRemap MemFile`. If the OS/FS
## supports it, file space is reserved to ensure room for new virtual pages.
## Caller should wait often enough for `flush` to finish to limit use of
## system RAM for write buffering, perhaps just prior to this call.
## **Note**: this assumes the entire file is mapped read-write at offset 0.
## Also, the value of `.mem` will probably change.
if newFileSize < 1: # Q: include system/bitmasks & use PageSize ?
raise newException(IOError, "Cannot resize MemFile to < 1 byte")
when defined(windows):
if not f.wasOpened:
raise newException(IOError, "Cannot resize unopened MemFile")
if f.fHandle == INVALID_HANDLE_VALUE:
raise newException(IOError,
"Cannot resize MemFile opened with allowRemap=false")
if unmapViewOfFile(f.mem) == 0 or closeHandle(f.mapHandle) == 0: # Un-do map
raiseOSError(osLastError())
if newFileSize != f.size: # Seek to size & `setEndOfFile` => allocated.
if (let e = setFileSize(f.fHandle.FileHandle, newFileSize);
e != 0.OSErrorCode): raiseOSError(e)
f.mapHandle = createFileMappingW(f.fHandle, nil, PAGE_READWRITE, 0,0,nil)
if f.mapHandle == 0: # Re-do map
raiseOSError(osLastError())
if (let m = mapViewOfFileEx(f.mapHandle, FILE_MAP_READ or FILE_MAP_WRITE,
0, 0, WinSizeT(newFileSize), nil); m != nil):
f.mem = m
f.size = newFileSize
else:
raiseOSError(osLastError())