"

 COPYRIGHT (c) 1997 by eXept Software AG

              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:libbasic2' }"

"{ NameSpace: Smalltalk }"

Object subclass:#DirectoryContents

	instanceVariableNames:'directory timeStamp contents isReadable isRootDirectory accessKey'

	classVariableNames:'CachedDirectories LockSema ReadersList'

	poolDictionaries:''

	category:'System-Support'

!

Object subclass:#DirectoryContentsItem

	instanceVariableNames:'info fileName'

	classVariableNames:'CachedRemoteMountPoints CachedRemoteMountPointsTimeStamp'

	poolDictionaries:''

	privateIn:DirectoryContents

!

!DirectoryContents class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1997 by eXept Software AG

              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

"

    DirectoryContents provides a cached view onto a fileDirectory.

    Notice:

        This class is not available in other ST-systems;

        Applications using it may not be portable.

    [author:]

        Claus Atzkern

    [see also:]

        Filename

        FileStream DirectoryStream OperatingSystem

"

! !

!DirectoryContents class methodsFor:'initialization'!

initialize

    "setup lock-mechanism

    "

    LockSema    := RecursionLock new.

    ReadersList := Dictionary new.

! !

!DirectoryContents class methodsFor:'instance creation'!

new

    ^ self basicNew initialize

! !

!DirectoryContents class methodsFor:'accessing'!

cachedDirectoryNamed:aFileOrString

    "answer the valid cached directory or nil"

    ^ self directoryAt:aFileOrString

!

directoryNamed:aDirectory

    "returns the DirectoryContents for a directory named 

     aDirectoryName, aString, nil or Filename

    "

    |directory contents lockRead pathName addToList|

    aDirectory isNil ifTrue:[^ nil].

    directory := aDirectory asFilename.

    directory exists ifFalse:[ ^ nil ].

    directory := directory asAbsoluteFilename.

    contents := nil.

    LockSema critical:[

        CachedDirectories notNil ifTrue:[

            "/ remove all obsolete directories - without doing a system call

            CachedDirectories := CachedDirectories select:[:aDir| aDir timeStamp notNil ].

            contents := self directoryAt:directory.

            contents isNil ifTrue:[

                |n max|

                max := self maxCachedDirectories.

                CachedDirectories size > max ifTrue:[

                    "/ remove directories with contents less 64 and not obsolete (system call)

                    CachedDirectories := CachedDirectories

                        select:[:aDir| (aDir size > 64 and:[aDir isObsolete not]) ].

                    n := CachedDirectories size + 2 - max.

                    n > 0 ifTrue:[

                        "/ remove oldest directories

                        CachedDirectories removeLast:n.

                    ].

                ].

            ].

        ].

        contents isNil ifTrue:[

            ReadersList isNil ifTrue:[ReadersList := Dictionary new].

            pathName := directory pathName.

            lockRead := ReadersList at:pathName ifAbsentPut:[Semaphore forMutualExclusion].

        ]

    ].

    contents notNil ifTrue:[^ contents].

    addToList := false.

    lockRead critical:[

        [  "/ test whether another task got the semaphore and

           "/ has read the directory contents

           (contents := self directoryAt:directory) isNil ifTrue:[

                "/ read the directory contents

                contents  := self new directory:directory.

                "/ only cache if the mod'Time is valid.

                addToList := contents timeStamp notNil.

            ]

        ] ensure:[

            LockSema critical:[

                addToList ifTrue:[

                    CachedDirectories isNil ifTrue:[

                        CachedDirectories := OrderedCollection new

                    ].

                    CachedDirectories add:contents

                ].

                (lockRead isEmpty and:[ReadersList notNil]) ifTrue:[

                    ReadersList removeKey:pathName ifAbsent:nil

                ]

            ]

        ]

    ].    

    ^ contents

! !

!DirectoryContents class methodsFor:'cache flushing'!

flushCache

    "flush list of remembered directory contents"

    LockSema critical:[ CachedDirectories := nil ].

    "

     self flushCache

    "

    "Created: / 11.2.2000 / 00:13:59 / cg"

!

flushCachedDirectoryFor:aDirectoryOrString

    "remove directory from cache

    "

    |directory|

    aDirectoryOrString isNil ifTrue:[^ self ].                   

    directory := aDirectoryOrString asFilename.

    directory isSymbolicLink ifTrue:[^ self].

    self

        directoryAt:directory

        checkForValidContentsDo:[:aDirectory| false ].  "/ should be removed from cache

!

lowSpaceCleanup

    "flush list of remembered directory contents when low on memory"

    self flushCache

    "

     self lowSpaceCleanup

    "

    "Created: / 18.2.1998 / 18:17:05 / cg"

    "Modified: / 24.9.1998 / 17:51:15 / cg"

! !

!DirectoryContents class methodsFor:'constants'!

maxCachedDirectories

    "returns number of maximum cached directories

    "

    ^ 20

    "Modified: / 25.2.1998 / 19:56:24 / cg"

! !

!DirectoryContents class methodsFor:'private'!

accessKeyForDirectory:aDirectoryOrString

    "computes a fast access key to retrieve the directory in the cache

    "

    |key last|

    aDirectoryOrString isNil ifTrue:[^ nil ].

    aDirectoryOrString isFilename ifTrue:[ key := aDirectoryOrString nameString ]

                                 ifFalse:[ key := aDirectoryOrString ].

    key size > 1 ifTrue:[

        last := key last.

        (last == $/ or:[last == $\]) ifTrue:[

            ^ key copyButLast:1.

        ].

    ].

    ^ key

!

directoryAt:aFileOrString

    "checks whether directory already exists and is valid.

     If true the directory is returned otherwise nil

    "

    ^ self

        directoryAt:aFileOrString

        checkForValidContentsDo:[:aContents| aContents isObsolete not ].

!

directoryAt:aFileOrString checkForValidContentsDo:checkIsValidBlock

    "answer the directoryContents stored under aFileOrString in the cache.

     If the evaluation of the checkIsValidBlock returns false, the contents

     will be removed from the cache and nil is returned."

    |index directory file fastKey|

    fastKey := self accessKeyForDirectory:aFileOrString.

    fastKey isNil ifTrue:[^ nil ].  "/ the name is nil

    directory := nil.

    LockSema critical:[

        CachedDirectories notNil ifTrue:[

            index := CachedDirectories findFirst:[:d| d accessKey = fastKey ].

            index == 0 ifTrue:[

                file  := aFileOrString asFilename asAbsoluteFilename.

                index := CachedDirectories findFirst:[:d| d directory = file ].

            ].

            index ~~ 0 ifTrue:[

                directory := CachedDirectories removeAtIndex:index.

                (checkIsValidBlock value:directory) ifTrue:[

                    "/ keep the last accessed directory at end

                    CachedDirectories add:directory.

                ] ifFalse:[

                    "/ validation block answers false - return nil and removed from cache

                    directory := nil.

                ].

            ].

        ].

    ].

    ^ directory

! !

!DirectoryContents class methodsFor:'queries'!

directoryNamed:aDirectoryName detect:aTwoArgBlock

    "evaluate the block, [:filename :isDirectory] on the directory

     contents of a directory named aDirectoryName, until the block

     returns true. If nothing detected false is returned

    "

    ^ self directoryNamed:aDirectoryName detect:aTwoArgBlock onOpenErrorDo:nil

!

directoryNamed:aDirectoryName detect:aTwoArgBlock onOpenErrorDo:exceptionBlock

    "evaluate the block, [:filename :isDirectory] on the directory

     contents of a directory named aDirectoryName, until the block

     returns true. If nothing detected false is returned.

     if the directory cannot be open, the exceptionBlock is processed

     with the filename.

    "

    |directory contents isReadable file|

    directory := aDirectoryName asFilename.

    contents  := self directoryAt:directory.

    contents notNil ifTrue:[

        (isReadable := contents isReadable) ifTrue:[

            contents contentsDo:[:aFile :isDir|

                (aTwoArgBlock value:aFile value:isDir) ifTrue:[^ true]

            ].

            ^ false.

        ].

    ] ifFalse:[

        (isReadable := directory exists) ifTrue:[

            [

                directory directoryContentsDo:[:fn |

                    file := directory construct:fn.

                    (aTwoArgBlock value:file value:(file isDirectory)) ifTrue:[

                        ^ true

                    ]

                ].

                isReadable := false.

            ].

        ].

    ].

    (isReadable not and:[exceptionBlock notNil]) ifTrue:[

        exceptionBlock value:directory.

    ].

    ^ false

! !

!DirectoryContents class methodsFor:'startup & release'!

preSnapshot

    "flush list of cached directory contents before saving a snapshot

     (do not save them in the image)"

    self flushCache.

! !

!DirectoryContents class methodsFor:'utilities'!

contentsItemForFileName:aFilenameOrString 

    | aFilename directory directoryContents|

    aFilename := aFilenameOrString asFilename.

    directory := aFilename directory.

    directoryContents := self directoryAt:directory.

    directoryContents notNil ifTrue:[

        directoryContents itemsDo:[:fileItemThere |

            fileItemThere fileName = aFilename ifTrue:[

                ^ fileItemThere.

            ].

        ].

    ].

    aFilename exists ifFalse:[

        directoryContents notNil ifTrue:[ directoryContents beObsolete ].

        ^ nil

    ].

    ^ (DirectoryContentsItem new fileName:aFilename) info:aFilename info.

! !

!DirectoryContents methodsFor:'accessing'!

accessKey

    ^ accessKey

!

beObsolete

    "mark self as obsolete

     clear contents and reset time"

    |saveCont|

    timeStamp := nil.

    saveCont  := contents.

    contents  := #().

    saveCont notEmptyOrNil ifTrue:[

        "/ clear the info - if someone has a reference to the item

        saveCont do:[:eachItem | eachItem resetInfo ].

    ].

!

directory

    "returns the directoy name as Filename

    "

    ^ directory

!

modificationTime

    "get the last modification time of the directory.

     Note that sometimes a root directory does not return

     a valid modification time - so do not cache it."

    |modifyTime|

    timeStamp isNil ifTrue:[^ nil].

    modifyTime := directory modificationTime.

    modifyTime notNil ifTrue:[

        ^ modifyTime 

   ].

    isRootDirectory ifFalse:[

        "if it is not a root directory, assume that we have no access"

        isReadable := false.

        self beObsolete.

    ].

    ^ nil

!

timeStamp

    "get the last timeStamp (when the directory info was read) of the directory

    "

    ^ timeStamp

! !

!DirectoryContents methodsFor:'enumerating'!

contentsAndBaseNamesDo:aThreeArgBlock

    "evaluate the block on each file; the argument to the block is the

     filename, the baseName and true in case of a directory

     block arguments: [:fileName :aBaseName :isDirectory|

    "

    self itemsDo:[:eachItem |

        aThreeArgBlock 

            value:(eachItem fileName) 

            value:(eachItem baseName ) 

            value:(eachItem isDirectory)

    ].

!

contentsDo:aTwoArgBlock

    "evaluate the block on each file; the argument to the block is the

     filename and true in case of a directory

     block arguments: [:fileName :isDirectory|

    "

    self itemsDo:[:eachItem |

        aTwoArgBlock

            value:(eachItem fileName) 

            value:(eachItem isDirectory)

    ].

!

directoriesAndBasenamesDo:aTwoArgBlock

    "evaluate block on each directory; a Filename and Basename.

     The directories are sorted

    "

    self itemsDo:[:eachItem |

        eachItem isDirectory ifTrue:[

            aTwoArgBlock value:(eachItem fileName) value:(eachItem baseName)

        ]

    ]

!

directoriesDo:aOneArgBlock

    "evaluate block on each directory; a Filename. The directories are sorted

    "

    self itemsDo:[:eachItem |

        eachItem isDirectory ifTrue:[

            aOneArgBlock value:(eachItem fileName) 

        ]

    ].

!

filesAndBasenamesDo:aTwoArgBlock

    "evaluate block on each file; a Filename and a Basename.

     The files are sorted.

    "

    self itemsDo:[:eachItem |

        eachItem isDirectory ifFalse:[

            aTwoArgBlock value:(eachItem fileName) value:(eachItem baseName)

        ]

    ]

!

filesDo:aOneArgBlock

    "evaluate block on each file; a Filename. The files are sorted.

    "

    self itemsDo:[:eachItem |