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Implement readInto and read(n)

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Zahary Karadjov 2020-05-01 21:39:08 +03:00
commit bf930b6f1b
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12 changed files with 636 additions and 220 deletions
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45
faststreams/outputs.nim
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@ -35,10 +35,10 @@ type
AsyncOutputStream* {.borrow: `.`.} = distinct OutputStream
WriteSyncProc* = proc (s: OutputStream, buf: pointer, bufLen: Natural)
WriteSyncProc* = proc (s: OutputStream, src: pointer, srcLen: Natural)
{.nimcall, gcsafe, raises: [IOError, Defect].}
WriteAsyncProc* = proc (s: OutputStream, buf: pointer, bufLen: Natural): Future[void]
WriteAsyncProc* = proc (s: OutputStream, src: pointer, srcLen: Natural): Future[void]
{.nimcall, gcsafe, raises: [IOError, Defect].}
FlushSyncProc* = proc (s: OutputStream)
@ -174,22 +174,13 @@ template ensureRunway*(s: AsyncOutputStream, neededRunway: Natural) =
ensureRunway OutputStream(s, neededRunway)
let FileOutputVTable = OutputStreamVTable(
writeSync: proc (s: OutputStream, buf: pointer, bufLen: Natural)
writeSync: proc (s: OutputStream, src: pointer, srcLen: Natural)
{.nimcall, gcsafe, raises: [IOError, Defect].} =
var file = FileOutputStream(s).file
template fail =
raise newException(IOError, "Failed to write OutputStream page.")
if s.buffers != nil:
s.buffers.consumeAllPages(pageAddr, pageLen):
let written = file.writeBuffer(pageAddr, pageLen)
if written != pageLen: fail()
if bufLen > 0:
doAssert buf != nil
var written = file.writeBuffer(buf, bufLen)
if written != bufLen: fail()
implementWrites(s.buffers, src, srcLen, "FILE",
writeStartAddr, writeLen):
file.writeBuffer(writeStartAddr, writeLen)
,
flushSync: proc (s: OutputStream)
{.nimcall, gcsafe, raises: [IOError, Defect].} =
@ -605,11 +596,12 @@ template consumeOutputs*(sp: OutputStream, bytesVar, body: untyped) =
## Please note that calling `consumeOutputs` on an unbuffered stream
## or an unsafe memory stream is considered a Defect.
##
## Before consuming the outputs, all outstanding delayed writes must be finalized.
## Before consuming the outputs, all outstanding delayed writes must
## be finalized.
let s = sp
doAssert s.extCursorsCount == 0 and s.buffers != nil
consumeAllPages(s.buffers, pageStartAddr, pageLen):
for pageStartAddr, pageLen in consumePageBuffers(s.buffers):
template bytesVar: untyped =
makeOpenArray(pageStartAddr, pageLen)
@ -619,15 +611,20 @@ template consumeContiguousOutput*(sp: OutputStream, bytesVar, body: untyped) =
## Please note that calling `consumeContiguousOutput` on an unbuffered stream
## or an unsafe memory stream is considered a Defect.
##
## Before consuming the output, all outstanding delayed writes must be finalized.
## Before consuming the output, all outstanding delayed writes must
## be finalized.
##
# TODO: This code is a bit too much to be inlined. Maybe this should be a proc
# with a callback, but this will restrict the types of variables it can write to.
# OTOH, perhaps only `consumeAllPages` is the offending part.
# TODO: This code is a bit too much to be inlined. Maybe this should be
# a proc with a callback, but this will restrict the types of variables
# it can write to. OTOH, perhaps only `consumePageBuffers` is the offending
# part.
var
s = sp
contigiousBytes: string # this may remain null
contigiousBytes: string
# this may remain null
# We are using a string, because `newStringOfCap` doesn't zero out
# the memory. TODO check if the same is true for `newSeqOfCap`.
bytesPtr: ptr byte
bytesLen: int
@ -643,7 +640,7 @@ template consumeContiguousOutput*(sp: OutputStream, bytesVar, body: untyped) =
else:
contigiousBytes = newStringOfCap(s.pos)
consumeAllPages(s.buffers, pageStartAddr, pageLen):
for pageStartAddr, pageLen in consumePageBuffers(s.buffers):
contigiousBytes.add makeOpenArray(cast[ptr char](pageStartAddr), pageLen)
bytesPtr = addr contigiousBytes[0]
@ -665,7 +662,7 @@ proc getOutput*(s: OutputStream, T: type string): string =
if s.buffers.queue.len == 1:
let page = s.buffers.queue[0]
if page.kind == stringPage and page.startOffset == 0:
if page.startOffset == 0:
result.swap page.data[]
result.setLen page.endOffset
# We clear the buffers, so the stream will be in pristine state.