LinePanelController.m

/*
     File: LinePanelController.m
 Abstract: "Select Line" panel controller for TextEdit.
 Enables selecting a single line, range of lines, from start or relative to current selected range.
 
  Version: 1.9
 
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#import "LinePanelController.h"
#import "TextEditErrors.h"
#import "TextEditMisc.h"
#import "Controller.h"

@implementation LinePanelController

- (id)init {
    return [super initWithWindowNibName:@"SelectLinePanel"];
}

- (void)windowDidLoad {
    NSWindow *window = [self window];
    [window setIdentifier:@"Line"];
    [window setRestorationClass:[self class]];
    [super windowDidLoad];  // It's documented to do nothing, but still a good idea to invoke...
}

/* Reopen the line panel when the app's persistent state is restored. 
*/
+ (void)restoreWindowWithIdentifier:(NSString *)identifier state:(NSCoder *)state completionHandler:(void (^)(NSWindow *, NSError *))completionHandler {
    completionHandler([[(Controller *)[NSApp delegate] lineController] window], NULL);
}

/* A short and sweet example of use of NSScanner. Parses user's line specification, in the form of N, or N-M, or +N-M, or -N-M. Returns NO on error. Assumes none of the out parameters are NULL!
*/
- (BOOL)parseLineDescription:(NSString *)desc fromLineSpec:(NSInteger *)fromLine toLineSpec:(NSInteger *)toLine relative:(NSInteger *)relative {
    NSScanner *scanner = [NSScanner localizedScannerWithString:desc];
    *relative = [scanner scanString:@"+" intoString:NULL] ? 1 : ([scanner scanString:@"-" intoString:NULL] ? -1 : 0);	    // Look for "+" or "-"; set relative to 1 or -1, or 0 if neither found
    if (![scanner scanInteger:fromLine]) return NO;	// Get the "from" spec
    if ([scanner scanString:@"-" intoString:NULL]) {	// If "-" seen, look for the "to" spec
	if (![scanner scanInteger:toLine] || (*toLine < *fromLine)) return NO;	    // There needs to be a number that is not less than the "from" spec
    } else {
	*toLine = *fromLine;				// If not a range, set the "to" spec to be the same as "from"
    }
    return [scanner isAtEnd] ? YES : NO;		// If more stuff, error. Note that the scanner skips over white space
}

/* getRange:... gets the range to be selected in the specified textView using the indicated start, end, and relative values
    If relative = 0, then select from start of fromLine to end of toLine. The first line of the text is line 1.
    If relative != 0 then select from start of fromLine lines from current selected range to toLine lines from current selected range.
      toLine == fromLine means a one-line selection
*/
- (BOOL)getRange:(NSRange *)rangePtr inTextView:(NSTextView *)textView fromLineSpec:(NSInteger)fromLine toLineSpec:(NSInteger)toLine relative:(NSInteger)relative {
    NSRange newSelection = {0, 0};	// Character locations for the new selection
    NSString *textString = [textView string];

    if (relative != 0) {		// Depending on relative direction, set the starting point to beginning of line at the start or end of the existing selected range
	NSRange curSel = [textView selectedRange];
	if (relative > 0) curSel.location = NSMaxRange(curSel) - ((curSel.length > 0) ? 1 : 0);
	[textString getLineStart:&newSelection.location end:NULL contentsEnd:NULL forRange:NSMakeRange(curSel.location, 0)];
    } else {
	if (fromLine == 0) return NO;	// "0" is not a valid absolute line spec
    }

    // At this point, newSelection.location points at the beginning of the line we want to start from
    if (relative < 0) {	    // Backwards relative from that spot
	for (NSInteger cnt = 1; cnt < fromLine; cnt++) {
	    if (newSelection.location == 0) return NO;	// Invalid specification
	    NSRange lineRange = [textString lineRangeForRange:NSMakeRange(newSelection.location - 1, 0)];
	    newSelection.location = lineRange.location;
	}
	NSInteger end = newSelection.location;	// This now marks the end of the range to be selected
	for (NSInteger cnt = fromLine; cnt <= toLine; cnt++) {
	    if (newSelection.location == 0) return NO;	// Invalid specification
	    NSRange lineRange = [textString lineRangeForRange:NSMakeRange(newSelection.location - 1, 0)];
	    newSelection.location = lineRange.location;
	}
	newSelection.length = end - newSelection.location;
    } else {		    // Forwards
	NSInteger textLength = [textString length];
	for (NSInteger cnt = (relative == 0) ? 1 : 0; cnt < fromLine; cnt++) {	// If not a relative selection, we start counting from 1, since the first line is "line 1" to the user
	    if (newSelection.location == textLength) return NO;	    // Invalid specification
	    NSRange lineRange = [textString lineRangeForRange:NSMakeRange(newSelection.location, 0)];
	    newSelection.location = NSMaxRange(lineRange);
	}
	NSInteger end = newSelection.location;
	for (NSInteger cnt = fromLine; cnt <= toLine; cnt++) {	// If not relative, the end of the range is an absolute line number; otherwise it's relative
	    if (end == textLength) return NO;    // Invalid specification
	    NSRange lineRange = [textString lineRangeForRange:NSMakeRange(end, 0)];
	    end = NSMaxRange(lineRange);
	}
	newSelection.length = end - newSelection.location;
    }
    if (rangePtr) *rangePtr = newSelection;
    return YES;
}

/* selectLinesUsingDescription:error: selects the specified lines. On error it returns NO and sets *error if not NULL.
*/
- (BOOL)selectLinesUsingDescription:(NSString *)desc error:(NSError **)error {
    id firstResponder = [[NSApp mainWindow] firstResponder];
    if ([firstResponder isKindOfClass:[NSTextView class]]) {
	NSInteger fromLine, toLine, relative;
	if (![self parseLineDescription:desc fromLineSpec:&fromLine toLineSpec:&toLine relative:&relative]) {
	    if (error) *error = [NSError errorWithDomain:TextEditErrorDomain code:TextEditInvalidLineSpecification userInfo:[NSDictionary dictionaryWithObjectsAndKeys:[NSString stringWithFormat:NSLocalizedStringFromTable(@"Invalid line specification \\U201c%@\\U201d.", @"LinePanel", @"Error message indicating invalid line specification for 'Select Line'"), truncatedString(desc, 100)], NSLocalizedDescriptionKey, NSLocalizedStringFromTable(@"Enter a line number or a range of line numbers to select.", @"LinePanel", @"Suggestion for correcting invalid line specification"), NSLocalizedRecoverySuggestionErrorKey, nil]];
	    return NO;
	}
	NSRange range;
        if (![self getRange:&range inTextView:firstResponder fromLineSpec:fromLine toLineSpec:toLine relative:relative]) {
	    if (error) *error = [NSError errorWithDomain:TextEditErrorDomain code:TextEditOutOfRangeLineSpecification userInfo:[NSDictionary dictionaryWithObjectsAndKeys:[NSString stringWithFormat:NSLocalizedStringFromTable(@"Invalid line specification \\U201c%@\\U201d.", @"LinePanel", @"Error message indicating invalid line specification for 'Select Line'"), truncatedString(desc, 100)], NSLocalizedDescriptionKey, NSLocalizedStringFromTable(@"Enter a line number or a range of line numbers to select.", @"LinePanel", @"Suggestion for correcting invalid line specification"), NSLocalizedRecoverySuggestionErrorKey, nil]];
	    return NO;
	}
	[firstResponder setSelectedRange:range];
	[firstResponder scrollRangeToVisible:range];
    }
    return YES;
}

/* If the user enters a line specification and hits return, we want to order the panel out if successful.  Hence this extra action method.
*/
- (IBAction)lineFieldChanged:(id)sender {
    NSError *error;
    if ([@"" isEqual:[sender stringValue]]) return;	// Don't do anything on empty string
    if ([self selectLinesUsingDescription:[sender stringValue] error:&error]) {
	[[self window] orderOut:nil];
    } else {
	[[self window] presentError:error];
	[[self window] makeKeyAndOrderFront:nil];
    }
}

/* Default action for the "Select" button.
*/
- (IBAction)selectClicked:(id)sender {
    NSError *error;
    if ([@"" isEqual:[lineField stringValue]]) return;	// Don't do anything on empty string
    if (![self selectLinesUsingDescription:[lineField stringValue] error:&error]) {
	[[self window] presentError:error];
	[[self window] makeKeyAndOrderFront:nil];
    }
}

@end