FileMan introduction @ Japanese and Korean Squeakers’ Night 2008. https://github.com/mumez/FileMan

1. Japanese and Korean Squeakers’ Night
2008 Masashi Umezawa

2. What is FileMan?
 Handy class libraries for handling files and
directories in Smalltalk
 Small
 Easy to use
 Portable (Squeak and VisualWorks)
 Extensible

3. File handling in Squeak
 We can use existing class libraries
 FileStream, FileDirectory, FilePath, etc
 Why FileMan?
 I feel frustrated...
○ Not well designed in OO way...
○ Need to write many codes...
○ I can imagine a simpler way...
 => Decided to start FileMan

4. How to get FileMan
 Squeak
 SqueakMap (Stable)
○ http://map.squeak.org/package/f9917683-25da-
4a6c-a013-b36527a100c1
 SqueakSourceJ (Current)
○ http://squeaksource.blueplane.jp/FileMan.html
 VisualWorks
 Cincom Public Store Repository

5. Sample code
 Create ’subDir’ directory under the current
directory, and make a text file named ’ file1.txt’
whose contents are ’Hello!’
 Normal
 FileMan
subDir := FileDirectory default directoryNamed: 'subDir'.
subDir assureExistence.
[str := subDir newFileNamed: 'file1.txt'.
str nextPutAll: 'Hello!']
ensure: [str close].
'./subDir' asDirectoryEntry at: 'file1.txt' put: 'Hello!'

6. FileMan’s strong point (1)
 Small
 Only three core classes
○ FmFileEntry
 represents file
○ FmDirectoryEntry
 represents directory
○ FmFileIOAccessor
 adapter for File I/O
(You are not aware of it except for porting
FileMan)

7. FileMan’s strong point(2)
 Easy to use
 All objects: Files and Directories
○ To File: Modification time? Size? Contents?
○ To Directory: Children files? Directories?
 just ask them!
 Dictionary-like API for Directory
○ key: file name, value: contents
○ For reading #at:, For writing: #at:put:

8. FileMan’s strong point(3)
 Portable
 Path representation is independent of platforms
○ ‘.¥subDir¥subSubDir’ asDirectoryEntry
is portable because
 runs on Win, Mac, Linux with no changes
- FileMan absorbs separator’s differences
○ ‘/tmp’ asDirectoryEntry at: ‘myData’ put: data
 is also portable
- runs on all platforms
- FileMan also attaches a ‘drive letter’ if necessary

9. FileMan’s strong point(4)
 Extensible
 By overriding FmDirectoryEntry, FmFileEntry
respectively, you can attach special behaviors
transparently
 Example: auto compress/uncompress
○ In #at:put:, a file ’text.gz’ will be created automatically
○ In #at:, ’text.gz’ will be uncompressed
| dir |
dir := './gzipped' asDirectoryEntry: FmGZipDirectoryEntry.
dir at: ‘text’ put: ‘I will be compressed'.
(dir at: 'text') inspect.

10. Example (1)
 Backup
 Backup all files under ‘foo’ directory into
‘bkUp’ subdirectories everyday
'./foo' asDirectoryEntry copyTo: './bkUp' / Date today yyyymmdd

11. Example (2)
 Error log
 Append error information to ‘error.log’ file
‘error.log’ asFileEntry appendContents: ‘Error...’

12. Example (3)
 Clean-up of dated files
 Clean up all ‘.txt’ extension files under ‘foo’ directory
that have not been updated for 100 days
dir := './foo' asDirectoryEntry.
current := TimeStamp current .
dir allFilesDo: [:file |
((file extension = 'txt') &
((TimeStamp fromSeconds: file modificationTime) plusDays: 100)< current)
ifTrue: [file delete]
].

13. Example (4)
 Text file conversion
 Convert all UTF-8, CR line-end text files
into Shift-JIS, CRLF line-end files
conv := [:in :out |
out wantsLineEndConversion: true; lineEndConvention: #crlf;
converter: ShiftJISTextConverter new.
out nextPutAll: (in upToEnd)
].
dir := './foo' asDirectoryEntry.
dir filesDo: [:file |
file pipe: conv to: (dir / (file name copyReplaceAll: '.txt' with: '.sjis.txt'))
]

14. Summary
 FileMan makes your program simple:
 powerful, simple classes for handling files and
directories
 Please use FileMan for daily tasks