diff options
Diffstat (limited to 'lib/pure/streams.nim')
| -rw-r--r-- | lib/pure/streams.nim | 128 |
1 files changed, 74 insertions, 54 deletions
diff --git a/lib/pure/streams.nim b/lib/pure/streams.nim index 50b3085d2..56f49d7b1 100644 --- a/lib/pure/streams.nim +++ b/lib/pure/streams.nim @@ -15,6 +15,11 @@ ## Other modules may provide other implementations for this standard ## stream interface. ## +## .. warning:: Due to the use of `pointer`, the `readData`, `peekData` and +## `writeData` interfaces are not available on the compile-time VM, and must +## be cast from a `ptr string` on the JS backend. However, `readDataStr` is +## available generally in place of `readData`. +## ## Basic usage ## =========== ## @@ -27,67 +32,67 @@ ## StringStream example ## -------------------- ## -## .. code-block:: Nim -## -## import std/streams +## ```Nim +## import std/streams ## -## var strm = newStringStream("""The first line -## the second line -## the third line""") +## var strm = newStringStream("""The first line +## the second line +## the third line""") ## -## var line = "" +## var line = "" ## -## while strm.readLine(line): -## echo line +## while strm.readLine(line): +## echo line ## -## # Output: -## # The first line -## # the second line -## # the third line +## # Output: +## # The first line +## # the second line +## # the third line ## -## strm.close() +## strm.close() +## ``` ## ## FileStream example ## ------------------ ## ## Write file stream example: ## -## .. code-block:: Nim +## ```Nim +## import std/streams ## -## import std/streams +## var strm = newFileStream("somefile.txt", fmWrite) +## var line = "" ## -## var strm = newFileStream("somefile.txt", fmWrite) -## var line = "" +## if not isNil(strm): +## strm.writeLine("The first line") +## strm.writeLine("the second line") +## strm.writeLine("the third line") +## strm.close() ## -## if not isNil(strm): -## strm.writeLine("The first line") -## strm.writeLine("the second line") -## strm.writeLine("the third line") -## strm.close() -## -## # Output (somefile.txt): -## # The first line -## # the second line -## # the third line +## # Output (somefile.txt): +## # The first line +## # the second line +## # the third line +## ``` ## ## Read file stream example: ## -## .. code-block:: Nim -## -## import std/streams +## ```Nim +## import std/streams ## -## var strm = newFileStream("somefile.txt", fmRead) -## var line = "" +## var strm = newFileStream("somefile.txt", fmRead) +## var line = "" ## -## if not isNil(strm): -## while strm.readLine(line): -## echo line -## strm.close() +## if not isNil(strm): +## while strm.readLine(line): +## echo line +## strm.close() ## -## # Output: -## # The first line -## # the second line -## # the third line +## # Output: +## # The first line +## # the second line +## # the third line +## ``` ## ## See also ## ======== @@ -98,6 +103,7 @@ import std/private/since when defined(nimPreviewSlimSystem): import std/syncio + export FileMode proc newEIO(msg: string): owned(ref IOError) = new(result) @@ -114,7 +120,7 @@ type ## * That these fields here shouldn't be used directly. ## They are accessible so that a stream implementation can override them. closeImpl*: proc (s: Stream) - {.nimcall, raises: [Exception, IOError, OSError], tags: [WriteIOEffect], gcsafe.} + {.nimcall, raises: [IOError, OSError], tags: [WriteIOEffect], gcsafe.} atEndImpl*: proc (s: Stream): bool {.nimcall, raises: [Defect, IOError, OSError], tags: [], gcsafe.} setPositionImpl*: proc (s: Stream, pos: int) @@ -173,10 +179,20 @@ proc close*(s: Stream) = ## See also: ## * `flush proc <#flush,Stream>`_ runnableExamples: - var strm = newStringStream("The first line\nthe second line\nthe third line") - ## do something... - strm.close() - if not isNil(s.closeImpl): s.closeImpl(s) + block: + let strm = newStringStream("The first line\nthe second line\nthe third line") + ## do something... + strm.close() + + block: + let strm = newFileStream("amissingfile.txt") + # deferring works even if newFileStream fails + defer: strm.close() + if not isNil(strm): + ## do something... + + if not isNil(s) and not isNil(s.closeImpl): + s.closeImpl(s) proc atEnd*(s: Stream): bool = ## Checks if more data can be read from `s`. Returns ``true`` if all data has @@ -337,9 +353,9 @@ proc write*[T](s: Stream, x: T) = ## **Note:** Not available for JS backend. Use `write(Stream, string) ## <#write,Stream,string>`_ for now. ## - ## .. code-block:: Nim - ## - ## s.writeData(s, unsafeAddr(x), sizeof(x)) + ## ```Nim + ## s.writeData(s, unsafeAddr(x), sizeof(x)) + ## ``` runnableExamples: var strm = newStringStream("") strm.write("abcde") @@ -927,10 +943,14 @@ proc peekFloat64*(s: Stream): float64 = proc readStrPrivate(s: Stream, length: int, str: var string) = if length > len(str): setLen(str, length) - when defined(js): - let L = readData(s, addr(str), length) + var L: int + when nimvm: + L = readDataStr(s, str, 0..length-1) else: - let L = readData(s, cstring(str), length) + when defined(js): + L = readData(s, addr(str), length) + else: + L = readData(s, cstring(str), length) if L != len(str): setLen(str, L) proc readStr*(s: Stream, length: int, str: var string) {.since: (1, 3).} = @@ -1471,7 +1491,7 @@ when false: # do not import windows as this increases compile times: discard else: - import posix + import std/posix proc hsSetPosition(s: FileHandleStream, pos: int) = discard lseek(s.handle, pos, SEEK_SET) @@ -1519,7 +1539,7 @@ when false: of fmReadWrite: flags = O_RDWR or int(O_CREAT) of fmReadWriteExisting: flags = O_RDWR of fmAppend: flags = O_WRONLY or int(O_CREAT) or O_APPEND - static: doAssert false # handle bug #17888 + static: raiseAssert "unreachable" # handle bug #17888 var handle = open(filename, flags) if handle < 0: raise newEOS("posix.open() call failed") result = newFileHandleStream(handle) |