Issue 3669 in pharo: Unified API for accessing stdio streams

Status: FixedWaitingToBePharoed
Owner: [hidden email]
Labels: Type-Squeak 1.3

New issue 3669 by [hidden email]: Unified API for accessing stdio  
streams
http://code.google.com/p/pharo/issues/detail?id=3669




Levente Uzonyi uploaded a new version of Files to project The Trunk:
http://source.squeak.org/trunk/Files-ul.96.mcz

==================== Summary ====================
it may be interesting for Coral and scripting.


Name: Files-ul.96
Author: ul
Time: 24 January 2011, 3:45:32.858 am
UUID: d06be799-4c77-3b46-aff8-4abc589fafd3
Ancestors: Files-mtf.95

Stdio support changes:
- Added  stdio support code to FileStream.
- Unified API for accessing stdio streams. All users should send #stdin,  
#stdout and #stderr to FileStream to access the streams.
- MultiByteFileStream is used instead of CrLfFileStream.
- CrLfFileStream class >> #new is now deprecated

=============== Diff against Files-mtf.95 ===============

Item was changed:
  StandardFileStream subclass: #CrLfFileStream
        instanceVariableNames: 'lineEndConvention'
        classVariableNames: 'Cr CrLf Lf LineEndDefault LineEndStrings  
LookAheadCount'
        poolDictionaries: ''
        category: 'Files-Kernel'!

+ !CrLfFileStream commentStamp: 'ul 12/26/2010 03:13' prior: 0!
+ This class is now obsolete, use MultiByteFileStream instead.
+
- !CrLfFileStream commentStamp: 'ls 11/10/2002 13:32' prior: 0!
  I am the same as a regular file stream, except that when I am in text  
mode, I will automatically convert line endings between the underlying  
platform's convention, and Squeak's convention of carriage-return only.  
The goal is that Squeak text files can be treated as OS text files, and  
vice versa.

  In binary mode, I behave identically to a StandardFileStream.

  To enable CrLfFileStream as the default file stream class for an entire  
image, modify FileStream class concreteStream .


  There are two caveats on programming with CrLfFileStream.

  First, the choice of text mode versus binary mode affects which characters  
are visible in Squeak, and no longer just affects whether those characters  
are returned as Character's or as Integer's.  Thus the choice of mode needs  
to be made very carefully, and must be based on intent instead of  
convenience of representation.  The methods asString, asByteArray,  
asCharacter, and asInteger can be used to convert between character and  
integer representations.  (Arguably, file streams should accept either  
strings or characters in nextPut: and nextPutAll:, but that is not the case  
right now.)

  Second, arithmetic on positions no longer works, because one character  
that Squeak sees (carriage return) could map to two characters in the  
underlying file (carriage return plus line feed, on MS Windows and MS  
DOS).  Comparison between positions still works.  (This caveat could  
perhaps be fixed by maintaining a map between Squeak positions and  
positions in the underlying file, but it is complicated.  Consider, for  
example, updates to the middle of the file.  Also, consider that text files  
are rarely updated in the middle of the file, and that general random  
access to a text file is rarely very useful.  If general random access with  
specific file counts is desired, then the file is starting to sound like a  
binary file instead of a text file.)

  !

Item was changed:
  ----- Method: CrLfFileStream class>>new (in category 'class  
initialization') -----
  new

+       self deprecated: 'This class is now obsolete, use  
MultiByteFileStream instead.'.
        ^ (MultiByteFileStream new) wantsLineEndConversion: true; yourself.

  !

Item was removed:
- ----- Method: CrLfFileStream class>>newForStdio (in category 'instance  
creation') -----
- newForStdio
-       "Circumvent CrLfFileStream new's retuning an instance of  
MultiBteFileStream"
-       ^super new!

Item was removed:
- ----- Method: CrLfFileStream>>openOnHandle:name:forWrite: (in  
category 'open/close') -----
- openOnHandle: aFileID name: streamName forWrite: writeMode
-       "Initialize the file with the given handle. If writeMode is true  
then
-        allow writing, otherwise put the file in read-only mode."
-       super openOnHandle: aFileID name: streamName forWrite: writeMode.
-       lineEndConvention := LineEndDefault!

Item was changed:
  ReadWriteStream subclass: #FileStream
        instanceVariableNames: 'rwmode'
+       classVariableNames: 'EncodeAndDecodeStdioFiles Stderr Stdin  
StdioFiles Stdout TheStdioHandles'
-       classVariableNames: ''
        poolDictionaries: ''
        category: 'Files-Kernel'!

  !FileStream commentStamp: '<historical>' prior: 0!
  I represent a Stream that accesses a FilePage from a File. One use for my  
instance is to access larger "virtual Strings" than can be stored  
contiguously in main memory. I restrict the objects stored and retrieved to  
be Integers or Characters. An end of file pointer terminates reading; it  
can be extended by writing past it, or the file can be explicitly truncated.

  To use the file system for most applications, you typically create a  
FileStream. This is done by sending a message to a FileDirectory (file:,  
oldFile:, newFile:, rename:newName:) which creates an instance of me.  
Accesses to the file are then done via my instance.

  *** On DOS, files cannot be shortened!!  ***  To overwrite a file with a  
shorter one, first delete the old file (FileDirectory deleteFilePath: 'Hard  
Disk:aFolder:dataFolder:foo') or (aFileDirectory deleteFileNamed: 'foo').  
Then write your new shorter version.!

Item was added:
+ ----- Method: FileStream class>>encodeAndDecodeStdioFiles (in  
category 'stdio') -----
+ encodeAndDecodeStdioFiles
+
+       <preference: 'Encode and decode the contents of stdio files.'
+               category: 'Files'
+               description: 'It true, then the contents of stdin, stdout  
and stderr are encoded/decoded using the system default text converter.'
+               type: #Boolean>
+       ^EncodeAndDecodeStdioFiles ifNil: [ true ]!

Item was added:
+ ----- Method: FileStream class>>encodeAndDecodeStdioFiles: (in  
category 'stdio') -----
+ encodeAndDecodeStdioFiles: aBoolean
+
+       EncodeAndDecodeStdioFiles := aBoolean.
+       self updateStdioFiles!

Item was added:
+ ----- Method: FileStream class>>flushAndVoidStdioFiles (in  
category 'stdio') -----
+ flushAndVoidStdioFiles
+
+       StdioFiles ifNotNil: [
+               StdioFiles do: [ :file |
+                       file ifNotNil: [
+                               file isReadOnly ifFalse: [
+                                       [ file flush ]
+                                               on: Error
+                                               do: [ :ex | "care less" ] ]  
] ].
+               self voidStdioFiles ]!

Item was changed:
  ----- Method: FileStream class>>initialize (in  
category 'initialize-release') -----
  initialize

+       FileServices registerFileReader: self.
+       EncodeAndDecodeStdioFiles := true.
+       TheStdioHandles := Array new: 3.
+       Smalltalk
+               addToStartUpList: self after: SecurityManager; "the intent  
being before: AutoStart"
+               addToShutDownList: self after: SecurityManager!
-       FileServices registerFileReader: self!

Item was added:
+ ----- Method: FileStream class>>newForStdio (in category 'stdio') -----
+ newForStdio
+       "This is a hook for subclasses to initialize themselves properly."
+
+       ^self new!

Item was added:
+ ----- Method: FileStream class>>shutDown: (in category 'system startup')  
-----
+ shutDown: quitting
+
+       quitting ifTrue: [ self flushAndVoidStdioFiles ]!

Item was added:
+ ----- Method: FileStream class>>standardIOStreamNamed:forWrite: (in  
category 'stdio') -----
+ standardIOStreamNamed: moniker forWrite: forWrite
+
+       | index |
+       index := #(stdin stdout stderr) identityIndexOf: moniker.
+       ^((StdioFiles ifNil: [ StdioFiles := Array new: 3 ]) at: index)
+               ifNil: [
+                       StdioFiles
+                               at: index
+                               put: (
+                                       (TheStdioHandles at: index)
+                                               ifNil: [ ^self error:  
moniker, ' is unavailable' ]
+                                               ifNotNil: [ :handle |
+                                                       self  
stdioStreamClass newForStdio
+                                                                
openOnHandle: handle
+                                                               name:  
moniker
+                                                               forWrite:  
forWrite ]) ]
+ !

Item was added:
+ ----- Method: FileStream class>>startUp: (in category 'system startup')  
-----
+ startUp: resuming
+
+       resuming ifTrue: [
+               self voidStdioFiles.
+               [ TheStdioHandles := self stdioHandles ]
+                       on: Error
+                       do: [:ex|
+                               TheStdioHandles isArray ifFalse: [
+                                       TheStdioHandles := Array new: 3 ] ]  
]!

Item was added:
+ ----- Method: FileStream class>>stderr (in category 'stdio') -----
+ stderr
+
+       ^Stderr ifNil: [ Stderr := self standardIOStreamNamed: #stderr  
forWrite: true ]!

Item was added:
+ ----- Method: FileStream class>>stdin (in category 'stdio') -----
+ stdin
+
+       ^Stdin ifNil: [ Stdin := self standardIOStreamNamed: #stdin  
forWrite: false ]!

Item was added:
+ ----- Method: FileStream class>>stdioHandles (in category 'stdio') -----
+ stdioHandles
+       <primitive: 'primitiveFileStdioHandles' module: 'FilePlugin' error:  
ec>
+       self primitiveFailed!

Item was added:
+ ----- Method: FileStream class>>stdioStreamClass (in category 'stdio')  
-----
+ stdioStreamClass
+
+       ^self encodeAndDecodeStdioFiles
+               ifTrue: [ MultiByteFileStream ]
+               ifFalse: [ StandardFileStream ]!

Item was added:
+ ----- Method: FileStream class>>stdout (in category 'stdio') -----
+ stdout
+
+       ^Stdout ifNil: [ Stdout := self standardIOStreamNamed: #stdout  
forWrite: true ]!

Item was added:
+ ----- Method: FileStream class>>updateStdioFiles (in category 'stdio')  
-----
+ updateStdioFiles
+       "Make sure that all existing stdio files are instances of  
#stdioStreamClass."
+
+       StdioFiles ifNil: [ ^self ].
+       Stdin := Stdout := Stderr := nil.
+       StdioFiles := StdioFiles collect: [ :file |
+               file ifNotNil: [
+                       file class == self stdioStreamClass
+                               ifTrue: [ file ]
+                               ifFalse: [
+                                       self stdioStreamClass newForStdio
+                                               copyFrom: file;
+                                               yourself ] ] ]
+ !

Item was added:
+ ----- Method: FileStream class>>voidStdioFiles (in category 'stdio') -----
+ voidStdioFiles
+
+        Stdin := Stdout := Stderr := StdioFiles := nil!