Hi all,

I've put some minutes summarizing the new APIs provided by the combination of the new File implementation and the Zn encoders. They all basically follow the decorator pattern to stack different responsibilities such as buffering, encoding, line ending convertions.

Please, do not hesitate to give your feedback.

Guille

1. Basic Files

By default files are binary. Not buffered.

(File named: 'name') readStream.

(File named: 'name') readStreamDo: [ :stream | ... ].

(File named: 'name') writeStream.

(File named: 'name') writeStreamDo: [ :stream | ... ].

2. Encoding

To add encoding, wrap a stream with a corresponding ZnCharacterRead/WriteStream.

"Reading"

utf8Encoded := ZnCharacterReadStream on: aBinaryStream encoding: 'utf8'.

utf16Encoded := ZnCharacterReadStream on: aBinaryStream encoding: 'utf16'.

"Writing"

utf8Encoded := ZnCharacterWriteStream on: aBinaryStream encoding: 'utf8'.

utf16Encoded := ZnCharacterWriteStream on: aBinaryStream encoding: 'utf16'.

3. Buffering

To add buffering, wrap a stream with a corresponding ZnBufferedRead/WriteStream.

bufferedReadStream := ZnBufferedReadStream on: aStream.

bufferedWriteStream := ZnBufferedWriteStream on: aStream.

It is in general better to buffer the reading on the binary file and apply the encoding on the buffer in memory than the other way around. See

[file := Smalltalk sourcesFile fullName.

(File named: file) readStreamDo: [ :binaryFile |

(ZnCharacterReadStream on: (ZnBufferedReadStream on: binaryFile) encoding: 'utf8') upToEnd

]] timeToRun. "0:00:00:09.288"

[file := Smalltalk sourcesFile fullName.

(File named: file) readStreamDo: [ :binaryFile |

(ZnBufferedReadStream on: (ZnCharacterReadStream on: binaryFile encoding: 'utf8')) upToEnd

]] timeToRun. "0:00:00:14.189"

4. File System

By default, file system files are buffered and utf8 encoded to keep backwards compatibility.

'name' asFileReference readStreamDo: [ :bufferedUtf8Stream | ... ].

'name' asFileReference writeStreamDo: [ :bufferedUtf8Stream | ... ].

FileStream also provides access to plain binary files using the #binaryRead/WriteStream messages. Binary streams are buffered by default also.

'name' asFileReference binaryReadStreamDo: [ :bufferedBinaryStream | ... ].

'name' asFileReference binaryWriteStreamDo: [ :bufferedBinaryStream | ... ].

If you want a file with another encoding (to come in the PR https://github.com/pharo-project/pharo/pull/1134), you can specify it while obtaining the stream:

'name' asFileReference

�� �� readStreamEncoded: 'utf16'

�� �� do: [ :bufferedUtf16Stream | ... ].

'name' asFileReference��

�� �� writeStreamEncoded: 'utf8'

�� �� do: [ :bufferedUtf16Stream | ... ].

5. Line Ending Conventions

If you want to write files following a specific line ending convention, use the ZnNewLineWriterStream.

This stream decorator will transform any line ending (cr, lf, crlf) into a defined line ending.

By default it chooses the platform line ending convention.

lineWriter := ZnNewLineWriterStream on: aStream.

If you want to choose another line ending convention you can do:

lineWriter forCr.

lineWriter forLf.

lineWriter forCrLf.

lineWriter forPlatformLineEnding.

--

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Guille Polito Research Engineer Centre de Recherche en Informatique, Signal et Automatique de Lille CRIStAL - UMR 9189 French National Center for Scientific Research - http://www.cnrs.fr Web: http://guillep.github.io Phone: +33 06 52 70 66 13