"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

"{ Package: 'stx:libbasic' }"

ExternalStream subclass:#NonPositionableExternalStream

	instanceVariableNames:''

	classVariableNames:'StdInStream StdOutStream StdErrorStream'

	poolDictionaries:''

	category:'Streams-External'

!

!NonPositionableExternalStream primitiveDefinitions!

%{

#ifndef _STDIO_H_INCLUDED_

# include <stdio.h>

# define _STDIO_H_INCLUDED_

#endif

%}

! !

!NonPositionableExternalStream class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    This class provides common protocol for all non-positionable,

    external streams. Concrete subclasses are terminal streams, pipe streams,

    PrinterStreams, Sockets etc.

    There are three special instances of this class, representing stdin,

    stdout and stderr of the smalltalk/X process (see Unix manuals, if you

    dont know what those are used for). These special streams are bound to

    to globals Stdin, Stdout and Stderr at early initialization time

    (see Smalltalk>>initializeStandardStreams).

    The name of this class is a historical leftover - it should be called

    'TTYStream' or similar.

    [author:]

	Claus Gittinger

"

! !

!NonPositionableExternalStream class methodsFor:'instance creation'!

forStderr

    "{ Pragma: +optSpace }"

    "return a NonPositionableExternalStream object for writing to

     Unixes standard error output file descriptor"

    StdErrorStream isNil ifTrue:[

	StdErrorStream := self basicNew initializeForStderr

    ].

    ^ StdErrorStream

!

forStdin

    "{ Pragma: +optSpace }"

    "return a NonPositionableExternalStream object for reading from

     Unixes standard input file descriptor"

    StdInStream isNil ifTrue:[

	StdInStream := self basicNew initializeForStdin

    ].

    ^ StdInStream

!

forStdout

    "{ Pragma: +optSpace }"

    "return a NonPositionableExternalStream object for writing to

     Unixes standard output file descriptor"

    StdOutStream isNil ifTrue:[

	StdOutStream := self basicNew initializeForStdout

    ].

    ^ StdOutStream

!

makePTYPair

    "return an array with two streams - the first one is the master, 

     the second the slave of a ptym/ptys pair.

     This is much like a bidirectional pipe, but allows signals &

     control chars to be passed through the connection.

     This is needed to execute a shell in a view.

     This is the higher level equivalent of OperatingSystem>>makePTYPair

     (which returns an array of file-descriptors)."

    |ptyPair master slave|

    ptyPair := OperatingSystem makePTYPair.

    ptyPair notNil ifTrue:[

	master := self forReadWriteToFileDescriptor:(ptyPair at:1).

	master buffered:false.

	slave := self forReadWriteToFileDescriptor:(ptyPair at:2).

	slave buffered:false.

	ptyPair at:1 put:master.

	ptyPair at:2 put:slave.

	^ ptyPair

    ].

    ^ nil

    "

     ExternalStream makePTYPair.

    "

    "Modified: 29.2.1996 / 18:28:36 / cg"

!

makePipe

    "return an array with two streams - the first one for reading, 

     the second for writing. 

     This is the higher level equivalent of OperatingSystem>>makePipe

     (which returns an array of file-descriptors)."

     |pipe rs ws|

     pipe := OperatingSystem makePipe.

     pipe notNil ifTrue:[

         rs := self forReadingFromFileDescriptor:(pipe at:1).

         rs buffered:false.

         ws := self forWritingToFileDescriptor:(pipe at:2).

         ws buffered:false.

         ^ Array with:rs with:ws

     ].

     ^ nil

    "

     |pipe rs ws|

     pipe := NonPositionableExternalStream makePipe.

     rs := pipe at:1.

     ws := pipe at:2.

     'read ...'.

     [

         1 to:10 do:[:i |

             Transcript showCR:rs nextLine

         ].

         rs close.

     ] forkAt:7.

     'write ...'.

     [

         1 to:10 do:[:i |

             ws nextPutAll:'hello world '; nextPutAll:i printString; cr

         ].

         ws close.

     ] fork.

    "

    "Modified: 29.2.1996 / 18:28:36 / cg"

! !

!NonPositionableExternalStream methodsFor:'error handling'!

positionError

    "{ Pragma: +optSpace }"

    "notify that this stream has no concept of a position"

    ^ PositionError raiseRequestWith:self

    "

     Stderr positionError

    "

! !

!NonPositionableExternalStream methodsFor:'non homogenous reading'!

nextBytes:count into:anObject startingAt:start

    "read the next count bytes into an object and return the number of

     bytes read or the number of bytes read, if EOF is encountered before.

     An exception is raised if the connection is broken.

     Redefined here to avoid blocking of ST/X when waiting for io.

     Instead only the calling thread will block"

    |remaining offset nRead|

    count == 0 ifTrue:[

        ^ 0.

    ].

    remaining := count.

    offset := start.

    [  

        nRead := self nextAvailableBytes:remaining into:anObject startingAt:offset.

        nRead == 0 ifTrue:[

            "atEnd does a readWait"

            self atEnd not.

        ] ifFalse:[

            remaining := remaining - nRead.

            offset := offset + nRead.

            remaining ~~ 0.

        ]

    ] whileTrue.

    ^ count - remaining

! !

!NonPositionableExternalStream methodsFor:'positioning'!

position

    "{ Pragma: +optSpace }"

    "catch position - there is none here"

    ^ self positionError

!

position:aPosition

    "{ Pragma: +optSpace }"

    "catch position - there is none here"

    ^ self positionError

!

skip:numberToSkip

    "skip count bytes/characters, return the receiver.

     Re-redefined since PositionableStream redefined it."

    "dont know how to unread ..."

    numberToSkip < 0 ifTrue:[

        PositionError raiseRequest.

        ^ self 

    ].

    numberToSkip timesRepeat:self next

    "Modified: / 30.7.1999 / 12:42:12 / cg"

!

skipThroughAll:aCollection

    "skip for and through the sequence given by the argument, aCollection;

     return nil if not found, the receiver otherwise. 

     On a successful match, the next read will return elements after aCollection;

     if no match was found, the receiver will be positioned at the end.

     Redefined to be the same as Stream>>#skipThroughAll, to undo

     the redefinition from PositionableStream"

    |buffer l first idx|

    l := aCollection size.

    first := aCollection at:1.

    [self atEnd] whileFalse:[

	buffer isNil ifTrue:[

	    buffer := self nextAvailable:l.

	].

	buffer = aCollection ifTrue:[

	    ^ self

	].

	idx := buffer indexOf:first startingAt:2.

	idx == 0 ifTrue:[

	    buffer := nil

	] ifFalse:[

	    buffer := (buffer copyFrom:idx) , (self nextAvailable:(idx - 1))

	]

    ].

    ^ nil

    "

     |s|

     s := ReadStream on:'12345678901234567890'.

     s skipThroughAll:'901'.

     s upToEnd                    

    "

    "

     |s|

     s := ReadStream on:'12345678901234567890'.

     s skipThroughAll:'1234'.

     s upToEnd                    

    "

    "

     |s|

     s := ReadStream on:'12345678901234567890'.

     s skipThroughAll:'999'.

     s atEnd                    

    "

    "Modified: / 11.1.1997 / 19:09:06 / cg"

    "Created: / 15.1.1998 / 23:33:37 / stefan"

! !

!NonPositionableExternalStream methodsFor:'printing & storing'!

printOn:aStream

    "{ Pragma: +optSpace }"

    "append a user printed representation of the receiver to aStream.

     The format is suitable for a human - not meant to be read back."

    |myName|

    self == Stdin ifTrue:[

        myName := 'Stdin'.

    ] ifFalse:[

        self == Stdout ifTrue:[

            myName := 'Stdout'.

        ] ifFalse:[

            self == Stderr ifTrue:[

                myName := 'Stderr'.

            ]

        ]

    ].

    myName notNil ifTrue:[

        aStream nextPutAll:myName.

        ^ self

    ].

    super printOn:aStream

!

storeOn:aStream

    "{ Pragma: +optSpace }"

    "append a printed representation of the receiver on aStream, from

     which the receiver can be reconstructed."

    ((self == Stdin)

    or:[self == Stdout

    or:[self == Stderr]]) ifTrue:[

	^ self printOn:aStream

    ].

    super storeOn:aStream

! !

!NonPositionableExternalStream methodsFor:'private'!

handleForStderr

    "{ Pragma: +optSpace }"

    "return a stderr handle"

%{

    RETURN ( __MKOBJ(stderr) );

%}

!

handleForStdin

    "{ Pragma: +optSpace }"

    "return a stdin handle"

%{

    RETURN ( __MKOBJ(stdin) );

%}

!

handleForStdout

    "{ Pragma: +optSpace }"

    "return a stdout handle"

%{

    RETURN ( __MKOBJ(stdout) );

%}

!

initializeForStderr

    "{ Pragma: +optSpace }"

    "setup for writing to stderr"

    mode := #readwrite.

    buffered := false.

    filePointer := self handleForStderr.

    OperatingSystem isMSWINDOWSlike ifTrue:[

        eolMode := #crlf

    ]

!

initializeForStdin

    "{ Pragma: +optSpace }"

    "setup for reading stdin"

    mode := #readonly.

    "/ buffered := true.

    buffered := false.

    filePointer := self handleForStdin.

!

initializeForStdout

    "{ Pragma: +optSpace }"

    "setup for writing to stdout"

    mode := #readwrite.

    buffered := false.

    filePointer := self handleForStdout.

    OperatingSystem isMSWINDOWSlike ifTrue:[

        eolMode := #crlf

    ]

!

reOpen

    "{ Pragma: +optSpace }"

    "reopen the stream after an image restart.

     If I am one of the standard streams, reopen is easy"

    (self == StdInStream) ifTrue:[

	^ self initializeForStdin

    ].

    (self == StdOutStream) ifTrue:[

	^ self initializeForStdout

    ].

    (self == StdErrorStream) ifTrue:[

	^ self initializeForStderr

    ].

    ^ super reOpen

! !

!NonPositionableExternalStream methodsFor:'queries'!

atEnd

    "return true, if position is at end"

    (self == StdInStream) ifTrue:[

	OperatingSystem hasConsole ifFalse:[

	    ^ true

	]

    ].

    "first, wait to avoid blocking on the read.

     On end of stream or error, readWait will return"

    self readWait.

    ^ super atEnd.

!

current

    "for compatibility with Transcript - allow Transcript current,

     even if redirected to the standardError"

    self == Transcript ifTrue:[

	^ self

    ].

    ^ super current

!

isPositionable

    "return true, if the stream supports positioning (this one is not)"

    ^ false

! !

!NonPositionableExternalStream methodsFor:'writing'!

nextPutBytes:initialWriteCount from:buffer startingAt:initialOffset

    "redefined, to wait until stream is writable, to avoid blocking in a write"

    |count offset remaining wasBlocking|

    offset := initialOffset.

    remaining := initialWriteCount.

    wasBlocking := self blocking:false.