"

 COPYRIGHT (c) 1994 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.

"

TwoColumnTextView subclass:#DiffTextView

	 instanceVariableNames:''

	 classVariableNames:''

	 poolDictionaries:''

	 category:'Views-Text'

!

DiffTextView comment:'

COPYRIGHT (c) 1994 by Claus Gittinger

	      All Rights Reserved

'!

!DiffTextView class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1994 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.

"

!

version

"

"

!

documentation

"

    a view showing diff (see unix manual pages) output in a 

    user-friendly form.

    The view is created and opened with:

       d := DiffTextView openOn:text1 and:text2.

    and it will show the differences side-by-side

    For a real world application, see the ChangesBrowsers

    compare function.

"

! !

!DiffTextView class methodsFor:'defaults'!

diffCommand

    ^ 'diff -b'

! !

!DiffTextView methodsFor:'private'!

updateListsFrom:text1 and:text2 diffs:diffList

    |idx1 idx2 dIdx dEnd state s nr1 nr2 nr3 op entry c l1 l2 any delta|

    l1 := OrderedCollection new.

    l2 := OrderedCollection new.

    idx1 := 1.

    idx2 := 1.

    dIdx := 1.

    dEnd := diffList size + 1.

    state := #initial.

    [dIdx <= dEnd] whileTrue:[

	dIdx == dEnd ifTrue:[

	    "dummy cleanup entry"

	    entry := nil.

	    state := #initial.

	] ifFalse:[

	    entry := diffList at:dIdx.

	].

	state == #initial ifTrue:[

	    "entry is of the form <nr> <op> <offs> [<offs2>]"

	    "

	     fill up to size difference from previous change

	    "

	    delta := l1 size - l2 size.

	    delta > 0 ifTrue:[

		delta timesRepeat:[l2 add:nil]

	    ] ifFalse:[

		delta < 0 ifTrue:[

		    delta negated timesRepeat:[l1 add:nil]

		]

	    ].

	    "

	     except for the first chunk, add a separating line

	    "

	    l1 size ~~ 0 ifTrue:[

		l1 add:'--------'.

		l2 add:'--------'.

	    ].

	    "

	     in cleanup ?

	    "

	    entry isNil ifTrue:[

		nr1 := text1 size + 1.

		nr2 := text2 size + 1.

		state := #finish.

	    ] ifFalse:[

		s := ReadStream on:entry.

		nr1 := Integer readFrom:s.

		s peek == $, ifTrue:[

		    s next.

		    Integer readFrom:s

		].

		op := s next.

		nr2 := Integer readFrom:s.

		s peek == $, ifTrue:[

		    s next.

		    nr3 := Integer readFrom:s

		] ifFalse:[

		    nr3 := nil

		].

		op == $c ifTrue:[

		    state := #changed.

		] ifFalse:[

		    op == $a ifTrue:[

			state := #added.

			l1 add:(text1 at:idx1).

			idx1 := idx1 + 1.

		    ] ifFalse:[

			op == $d ifTrue:[

			    state := #deleted

			]

		    ]

		].

	    ].

	    "

	     copy over unchanged lines

	    "

	    any := false.

	    [idx1 < nr1] whileTrue:[

		l1 add:(text1 at:idx1).

		idx1 := idx1 + 1.

		any := true.

	    ].

	    [idx2 < nr2] whileTrue:[

		l2 add:(text2 at:idx2).

		idx2 := idx2 + 1.

		any := true.

	    ].

	    "

	     add a separating line, except at end

	    "

	    any ifTrue:[

		state ~~ #finish ifTrue:[

		    l1 add:'--------'.

		    l2 add:'--------'.

		]

	    ].

	] ifFalse:[

	    state == #changed ifTrue:[

		(entry at:1) == $< ifTrue:[

		    l1 add:(text1 at:idx1).

		    idx1 := idx1 + 1

		] ifFalse:[

		    (entry at:1) == $> ifTrue:[

			l2 add:(text2 at:idx2).

			idx2 := idx2 + 1

		    ] ifFalse:[

			(entry at:1) == $- ifTrue:[

			] ifFalse:[

			    state := #initial.

			    dIdx := dIdx - 1

			]

		    ]

		]

	    ] ifFalse:[

		state == #added ifTrue:[

		    (entry at:1) == $> ifTrue:[

			l2 add:(text2 at:idx2).

			idx2 := idx2 + 1.

			l1 add:nil

		    ] ifFalse:[

			state := #initial.

			dIdx := dIdx - 1

		    ]

		] ifFalse:[

		    state == #deleted ifTrue:[

			(entry at:1) == $< ifTrue:[

			    l1 add:(text1 at:idx1).

			    idx1 := idx1 + 1.

			    l2 add:nil

			] ifFalse:[

			    state := #initial.

			    dIdx := dIdx - 1

			]

		    ] 

		    "must be in finish otherwise"

		]

	    ]

	].

	dIdx := dIdx + 1

    ].

    [l1 size < l2 size] whileTrue:[

	l1 add:''.

    ].

    [l2 size < l1 size] whileTrue:[

	l2 add:''.

    ].

    textView1 list:l1.

    textView2 list:l2

! !

!DiffTextView methodsFor:'accessing'!

text1:t1 text2:t2

    "

     save them texts in two temporary files ...

    "

    text1 do:[:line |

	stream nextPutAll:line; cr

    ].

    stream close.

    text2 do:[:line |

	stream nextPutAll:line; cr

    ].

    stream close.

    "

     start diff on it ...

    "

    stream := PipeStream 

		readingFrom:self class diffCommand , ' ' , 

    stream isNil ifTrue:[

	self error:'cannot execute diff'.

	text1 := text2 := nil.

    ] ifFalse:[

	diffList := OrderedCollection new.

	[stream atEnd] whileFalse:[

	    line := stream nextLine.

	    line notNil ifTrue:[diffList add:line]

	].

	stream close.

    ].

    self updateListsFrom:text1 and:text2 diffs:diffList

    "

     |v|

     v := HVScrollableView for:DiffTextView.

     v scrolledView text1:('../libview/Color.st' asFilename readStream contents)

		    text2:('../libview/Color.st.old' asFilename readStream contents).

     v open

    "

    "

     |v t1 t2|

     t1 := '

one

two

three

four

'.

     t2 := '

one

two-a

two-b

three

three-b

four

'.

     v := DiffTextView new.

     v text1:t1 text2:t2.

    "

! !