diff options
Diffstat (limited to 'lib/pure/memfiles.nim')
| -rw-r--r-- | lib/pure/memfiles.nim | 193 |
1 files changed, 112 insertions, 81 deletions
diff --git a/lib/pure/memfiles.nim b/lib/pure/memfiles.nim index 48c07b149..8eec551c4 100644 --- a/lib/pure/memfiles.nim +++ b/lib/pure/memfiles.nim @@ -16,15 +16,15 @@ ## other "line-like", variable length, delimited records). when defined(windows): - import winlean - when useWinUnicode and defined(nimPreviewSlimSystem): + import std/winlean + when defined(nimPreviewSlimSystem): import std/widestrs elif defined(posix): - import posix + import std/posix else: {.error: "the memfiles module is not supported on your operating system!".} -import streams +import std/streams import std/oserrors when defined(nimPreviewSlimSystem): @@ -35,6 +35,35 @@ proc newEIO(msg: string): ref IOError = new(result) result.msg = msg +proc setFileSize(fh: FileHandle, newFileSize = -1, oldSize = -1): OSErrorCode = + ## Set the size of open file pointed to by `fh` to `newFileSize` if != -1, + ## allocating | freeing space from the file system. This routine returns the + ## last OSErrorCode found rather than raising to support old rollback/clean-up + ## code style. [ Should maybe move to std/osfiles. ] + if newFileSize < 0 or newFileSize == oldSize: + return + when defined(windows): + var sizeHigh = int32(newFileSize shr 32) + let sizeLow = int32(newFileSize and 0xffffffff) + let status = setFilePointer(fh, sizeLow, addr(sizeHigh), FILE_BEGIN) + let lastErr = osLastError() + if (status == INVALID_SET_FILE_POINTER and lastErr.int32 != NO_ERROR) or + setEndOfFile(fh) == 0: + result = lastErr + else: + if newFileSize > oldSize: # grow the file + var e: cint # posix_fallocate truncates up when needed. + when declared(posix_fallocate): + while (e = posix_fallocate(fh, 0, newFileSize); e == EINTR): + discard + if e in [EINVAL, EOPNOTSUPP] and ftruncate(fh, newFileSize) == -1: + result = osLastError() # fallback arguable; Most portable BUT allows SEGV + elif e != 0: + result = osLastError() + else: # shrink the file + if ftruncate(fh.cint, newFileSize) == -1: + result = osLastError() + type MemFile* = object ## represents a memory mapped file mem*: pointer ## a pointer to the memory mapped file. The pointer @@ -125,7 +154,7 @@ proc open*(filename: string, mode: FileMode = fmRead, ## ## Example: ## - ## .. code-block:: nim + ## ```nim ## var ## mm, mm_full, mm_half: MemFile ## @@ -137,6 +166,7 @@ proc open*(filename: string, mode: FileMode = fmRead, ## ## # Read the first 512 bytes ## mm_half = memfiles.open("/tmp/test.mmap", mode = fmReadWrite, mappedSize = 512) + ## ``` # The file can be resized only when write mode is used: if mode == fmAppend: @@ -174,25 +204,13 @@ proc open*(filename: string, mode: FileMode = fmRead, else: FILE_ATTRIBUTE_NORMAL or flags, 0) - when useWinUnicode: - result.fHandle = callCreateFile(createFileW, newWideCString(filename)) - else: - result.fHandle = callCreateFile(createFileA, filename) + result.fHandle = callCreateFile(createFileW, newWideCString(filename)) if result.fHandle == INVALID_HANDLE_VALUE: fail(osLastError(), "error opening file") - if newFileSize != -1: - var - sizeHigh = int32(newFileSize shr 32) - sizeLow = int32(newFileSize and 0xffffffff) - - var status = setFilePointer(result.fHandle, sizeLow, addr(sizeHigh), - FILE_BEGIN) - let lastErr = osLastError() - if (status == INVALID_SET_FILE_POINTER and lastErr.int32 != NO_ERROR) or - (setEndOfFile(result.fHandle) == 0): - fail(lastErr, "error setting file size") + if (let e = setFileSize(result.fHandle.FileHandle, newFileSize); + e != 0.OSErrorCode): fail(e, "error setting file size") # since the strings are always 'nil', we simply always call # CreateFileMappingW which should be slightly faster anyway: @@ -226,7 +244,7 @@ proc open*(filename: string, mode: FileMode = fmRead, result.wasOpened = true if not allowRemap and result.fHandle != INVALID_HANDLE_VALUE: - if closeHandle(result.fHandle) == 0: + if closeHandle(result.fHandle) != 0: result.fHandle = INVALID_HANDLE_VALUE else: @@ -241,42 +259,31 @@ proc open*(filename: string, mode: FileMode = fmRead, flags = flags or O_CREAT or O_TRUNC var permissionsMode = S_IRUSR or S_IWUSR result.handle = open(filename, flags, permissionsMode) + if result.handle != -1: + if (let e = setFileSize(result.handle.FileHandle, newFileSize); + e != 0.OSErrorCode): fail(e, "error setting file size") else: result.handle = open(filename, flags) if result.handle == -1: - # XXX: errno is supposed to be set here - # Is there an exception that wraps it? fail(osLastError(), "error opening file") - if newFileSize != -1: - if ftruncate(result.handle, newFileSize) == -1: - fail(osLastError(), "error setting file size") - - if mappedSize != -1: - result.size = mappedSize - else: - var stat: Stat + if mappedSize != -1: #XXX Logic here differs from `when windows` branch .. + result.size = mappedSize #.. which always fstats&Uses min(mappedSize, st). + else: # if newFileSize!=-1: result.size=newFileSize # if trust setFileSize + var stat: Stat #^^.. BUT some FSes (eg. Linux HugeTLBfs) round to 2MiB. if fstat(result.handle, stat) != -1: - # XXX: Hmm, this could be unsafe - # Why is mmap taking int anyway? - result.size = int(stat.st_size) + result.size = stat.st_size.int # int may be 32-bit-unsafe for 2..<4 GiB else: fail(osLastError(), "error getting file size") result.flags = if mapFlags == cint(-1): MAP_SHARED else: mapFlags - #Ensure exactly one of MAP_PRIVATE cr MAP_SHARED is set + # Ensure exactly one of MAP_PRIVATE cr MAP_SHARED is set if int(result.flags and MAP_PRIVATE) == 0: result.flags = result.flags or MAP_SHARED - result.mem = mmap( - nil, - result.size, - if readonly: PROT_READ else: PROT_READ or PROT_WRITE, - result.flags, - result.handle, - offset) - + let pr = if readonly: PROT_READ else: PROT_READ or PROT_WRITE + result.mem = mmap(nil, result.size, pr, result.flags, result.handle, offset) if result.mem == cast[pointer](MAP_FAILED): fail(osLastError(), "file mapping failed") @@ -306,34 +313,58 @@ 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_t; flags: cint): - pointer {.importc: "mremap", header: "<sys/mman.h>".} - let newAddr = mremap(f.mem, csize_t(f.size), csize_t(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()) + elif defined(posix): + if f.handle == -1: + raise newException(IOError, + "Cannot resize MemFile opened with allowRemap=false") + if newFileSize != f.size: + if (let e = setFileSize(f.handle.FileHandle, newFileSize, f.size); + e != 0.OSErrorCode): raiseOSError(e) + 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_t; flags: cint): + pointer {.importc: "mremap", header: "<sys/mman.h>".} + let newAddr = mremap(f.mem, csize_t(f.size), csize_t(newFileSize), 1.cint) + 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 + f.size = newFileSize proc close*(f: var MemFile) = ## closes the memory mapped file `f`. All changes are written back to the @@ -381,7 +412,7 @@ proc `==`*(x, y: MemSlice): bool = proc `$`*(ms: MemSlice): string {.inline.} = ## Return a Nim string built from a MemSlice. result.setLen(ms.size) - copyMem(addr(result[0]), ms.data, ms.size) + copyMem(result.cstring, ms.data, ms.size) iterator memSlices*(mfile: MemFile, delim = '\l', eat = '\r'): MemSlice {.inline.} = ## Iterates over \[optional `eat`] `delim`-delimited slices in MemFile `mfile`. @@ -407,13 +438,13 @@ iterator memSlices*(mfile: MemFile, delim = '\l', eat = '\r'): MemSlice {.inline ## functions, not str* functions). ## ## Example: - ## - ## .. code-block:: nim + ## ```nim ## var count = 0 ## for slice in memSlices(memfiles.open("foo")): ## if slice.size > 0 and cast[cstring](slice.data)[0] != '#': ## inc(count) ## echo count + ## ``` proc c_memchr(cstr: pointer, c: char, n: csize_t): pointer {. importc: "memchr", header: "<string.h>".} @@ -443,11 +474,11 @@ iterator lines*(mfile: MemFile, buf: var string, delim = '\l', ## <#memSlices.i,MemFile,char,char>`_, but Nim strings are returned. ## ## Example: - ## - ## .. code-block:: nim + ## ```nim ## var buffer: string = "" ## for line in lines(memfiles.open("foo"), buffer): ## echo line + ## ``` for ms in memSlices(mfile, delim, eat): setLen(buf, ms.size) @@ -462,10 +493,10 @@ iterator lines*(mfile: MemFile, delim = '\l', eat = '\r'): string {.inline.} = ## <#memSlices.i,MemFile,char,char>`_, but Nim strings are returned. ## ## Example: - ## - ## .. code-block:: nim + ## ```nim ## for line in lines(memfiles.open("foo")): ## echo line + ## ``` var buf = newStringOfCap(80) for line in lines(mfile, buf, delim, eat): @@ -495,8 +526,8 @@ proc mmsSetPosition(s: Stream, pos: int) = proc mmsGetPosition(s: Stream): int = MemMapFileStream(s).pos proc mmsPeekData(s: Stream, buffer: pointer, bufLen: int): int = - let startAddress = cast[ByteAddress](MemMapFileStream(s).mf.mem) - let p = cast[ByteAddress](MemMapFileStream(s).pos) + let startAddress = cast[int](MemMapFileStream(s).mf.mem) + let p = cast[int](MemMapFileStream(s).pos) let l = min(bufLen, MemMapFileStream(s).mf.size - p) moveMem(buffer, cast[pointer](startAddress + p), l) result = l @@ -511,8 +542,8 @@ proc mmsWriteData(s: Stream, buffer: pointer, bufLen: int) = let size = MemMapFileStream(s).mf.size if MemMapFileStream(s).pos + bufLen > size: raise newEIO("cannot write to stream") - let p = cast[ByteAddress](MemMapFileStream(s).mf.mem) + - cast[ByteAddress](MemMapFileStream(s).pos) + let p = cast[int](MemMapFileStream(s).mf.mem) + + cast[int](MemMapFileStream(s).pos) moveMem(cast[pointer](p), buffer, bufLen) inc(MemMapFileStream(s).pos, bufLen) |