Implements a kind of live reloading (see Issue #22)

English.lproj/DiffDocument.xib

@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="4510" systemVersion="12F45" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none">
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="4514" systemVersion="13B42" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none">
     <dependencies>
-        <deployment version="1080" defaultVersion="1070" identifier="macosx"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="4510"/>
+        <deployment version="1080" defaultVersion="1080" identifier="macosx"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="4514"/>
     </dependencies>
     <objects>
         <customObject id="-2" userLabel="File's Owner" customClass="DiffDocument">
@@ -40,7 +40,7 @@
                                         <autoresizingMask key="autoresizingMask" widthSizable="YES" flexibleMaxX="YES" heightSizable="YES"/>
                                     </customView>
                                     <customView id="7" customClass="HFTextView">
-                                        <rect key="frame" x="332" y="0.0" width="321" height="356"/>
+                                        <rect key="frame" x="331.999999966948" y="0.0" width="321" height="356"/>
                                         <autoresizingMask key="autoresizingMask" flexibleMinX="YES" widthSizable="YES" heightSizable="YES"/>
                                     </customView>
                                 </subviews>
@@ -85,11 +85,11 @@
                                     </subviews>
                                     <color key="backgroundColor" name="controlBackgroundColor" catalog="System" colorSpace="catalog"/>
                                 </clipView>
-                                <scroller key="horizontalScroller" hidden="YES" verticalHuggingPriority="750" id="15">
+                                <scroller key="horizontalScroller" hidden="YES" verticalHuggingPriority="750" horizontal="YES" id="15">
                                     <rect key="frame" x="0.0" y="151" width="654.99999999999989" height="16"/>
                                     <autoresizingMask key="autoresizingMask"/>
                                 </scroller>
-                                <scroller key="verticalScroller" hidden="YES" verticalHuggingPriority="750" id="14">
+                                <scroller key="verticalScroller" hidden="YES" verticalHuggingPriority="750" horizontal="NO" id="14">
                                     <rect key="frame" x="-100" y="-100" width="15" height="167"/>
                                     <autoresizingMask key="autoresizingMask"/>
                                 </scroller>

English.lproj/MainMenu.xib

@@ -245,6 +245,12 @@
                                     </items>
                                 </menu>
                             </menuItem>
+                            <menuItem title="Reload Unmodified" id="bpc-ky-jvV">
+                                <modifierMask key="keyEquivalentModifierMask"/>
+                                <connections>
+                                    <action selector="setLiveReloadFromMenuItem:" target="-1" id="HRn-F2-u4k"/>
+                                </connections>
+                            </menuItem>
                             <menuItem isSeparatorItem="YES" id="214">
                                 <modifierMask key="keyEquivalentModifierMask" command="YES"/>
                             </menuItem>

app/sources/BaseDataDocument.h

@@ -48,7 +48,11 @@ NSString * const BaseDataDocumentDidChangeStringEncodingNotification;
     BOOL saveInProgress;
 
     BOOL currentlySettingFont;
-    BOOL isTransient;    
+    BOOL isTransient;
+
+    BOOL shouldLiveReload;
+    NSDate *liveReloadDate;
+    NSTimer *liveReloadTimer;
 }
 
 - (void)moveSelectionForwards:(NSMenuItem *)sender;
@@ -108,4 +112,8 @@ NSString * const BaseDataDocumentDidChangeStringEncodingNotification;
 
 - (BOOL)requiresOverwriteMode;
 
+- (BOOL)shouldLiveReload;
+- (void)setShouldLiveReload:(BOOL)flag;
+- (IBAction)setLiveReloadFromMenuItem:sender;
+
 @end

app/sources/BaseDataDocument.m

@@ -515,8 +515,9 @@ - (id)init {
 
     controller = [[HFController alloc] init];
     [controller setShouldAntialias:[defs boolForKey:@"AntialiasText"]];
-    [controller setShouldShowCallouts:[defs boolForKey:@"ShowCallouts"]];
     [controller setShouldColorBytes:[defs boolForKey:@"ColorBytes"]];
+    [controller setShouldShowCallouts:[defs boolForKey:@"ShowCallouts"]];
+    [controller setShouldLiveReload:[defs boolForKey:@"LiveReload"]];
     [controller setUndoManager:[self undoManager]];
     [controller setBytesPerColumn:[defs integerForKey:@"BytesPerColumn"]];
     [controller addRepresenter:layoutRepresenter];
@@ -565,6 +566,10 @@ - (void)dealloc {
     }
     [containerView release];
     [bannerDividerThumb release];
+
+    [liveReloadDate release];
+    [liveReloadTimer release];
+
     [super dealloc];
 }
 
@@ -823,12 +828,16 @@ - (BOOL)validateMenuItem:(NSMenuItem *)item {
         [item setState:[controller shouldAntialias]];
         return YES;
     }
+    else if (action == @selector(setColorBytesFromMenuItem:)) {
+        [item setState:[controller shouldColorBytes]];
+        return YES;
+    }
     else if (action == @selector(setShowCalloutsFromMenuItem:)) {
         [item setState:[controller shouldShowCallouts]];
         return YES;
     }
-    else if (action == @selector(setColorBytesFromMenuItem:)) {
-        [item setState:[controller shouldColorBytes]];
+    else if (action == @selector(setLiveReloadFromMenuItem:)) {
+        [item setState:[controller shouldLiveReload]];
         return YES;
     }
     else if (action == @selector(setOverwriteMode:)) {
@@ -1824,4 +1833,96 @@ - (BOOL)requiresOverwriteMode
     return NO;
 }
 
+- (BOOL)shouldLiveReload {
+    return shouldLiveReload;
+}
+
+- (void)setShouldLiveReload:(BOOL)flag {
+    shouldLiveReload = flag;
+    if(flag) [self pollLiveReload];
+}
+
+- (IBAction)setLiveReloadFromMenuItem:(id)sender {
+    USE(sender);
+    BOOL newVal = ![controller shouldLiveReload];
+    [controller setShouldLiveReload:newVal];
+    [[NSUserDefaults standardUserDefaults] setBool:newVal forKey:@"LiveReload"];
+    [self setShouldLiveReload:newVal];
+}
+
+@end
+
+// Let the compiler know about the 10.9 -[NSTimer setTolerance:] selector
+// even though we're targeting several versions behind that.
+@protocol MyNSTimerSetToleranceProtocol
+- (void)setTolerance:(NSTimeInterval)tolerance;
+@end
+
+@implementation BaseDataDocument(LiveReloading)
+
+// TODO: Some of the other NSFilePresenter methods could be used to make a
+// more versitle live-updating option.
+
+// Also, there may be a race conditon here: if a file being operated on
+// is swapped with another file during the live reload and just before the
+// live reload actually starts reverting, it may be that we revert to the
+// swapped in file rather than the actual file. I'm dubious that the use
+// of NSFileCoordinator here saves us from this, but it might. Even with
+// the race, there's no strong data loss concern; it just might happen that,
+// in extreme conditions, an unmodified document becomes a different document.
+// TODO: Investigate this.
+
+#define LiveReloadTimeTolerance 1.0 // Allow Cab some slack.
+#define LiveReloadTimeThrottle 1.0  // Auto reload at most every second.
+
+- (void)presentedItemDidChange {
+    // Stay in sync with changes if there are no outstanding edits and an
+    // update check is not already scheduled.
+    [self pollLiveReload];
+}
+
+- (void)pollLiveReload {
+    if(!shouldLiveReload) return;
+    if([self isDocumentEdited]) return; // Don't clobber changes.
+    if(liveReloadTimer && [liveReloadTimer isValid]) return; // A live reload is already scheduled.
+
+    NSDate *nextDate;
+    if(liveReloadDate && [liveReloadDate timeIntervalSinceNow] > -LiveReloadTimeThrottle) {
+        // Happened recently, throttle a bit.
+        nextDate = [liveReloadDate dateByAddingTimeInterval:LiveReloadTimeThrottle];
+    } else {
+        // Did not update recently, update soon.
+        nextDate = [NSDate date];
+    }
+
+    [liveReloadTimer release];
+    liveReloadTimer = [[NSTimer alloc] initWithFireDate:nextDate interval:0 target:self selector:@selector(tryLiveReload) userInfo:nil repeats:NO];
+
+    if([liveReloadTimer respondsToSelector:@selector(setTolerance:)]) {
+        [(id<MyNSTimerSetToleranceProtocol>)liveReloadTimer setTolerance:LiveReloadTimeTolerance];
+    }
+    [[NSRunLoop mainRunLoop] addTimer:liveReloadTimer forMode:NSDefaultRunLoopMode];
+}
+
+- (BOOL)tryLiveReload {
+    if(!shouldLiveReload) return NO;
+    if([self isDocumentEdited]) return NO; // Don't clobber changes.
+
+    NSError *error = nil;
+    NSError **errorp = &error;
+
+    [[[NSFileCoordinator alloc] initWithFilePresenter:self] coordinateReadingItemAtURL:[self fileURL] options:0 error:errorp byAccessor:^ (NSURL *url) {
+        NSDictionary *attrs = [[NSFileManager defaultManager] attributesOfItemAtPath:[[url filePathURL] path] error:errorp];
+        if(!attrs || *errorp) return;
+        if([[attrs objectForKey:NSFileModificationDate] isGreaterThan:[self fileModificationDate]]) {
+            [self revertToContentsOfURL:url ofType:[self fileType] error:errorp];
+        }
+    }];
+
+    [liveReloadDate release];
+    liveReloadDate = [[NSDate date] retain];
+
+    return error ? NO : YES;
+}
+
 @end

framework/sources/HFController.h

@@ -134,14 +134,15 @@ You create an HFController via <tt>[[HFController alloc] init]</tt>.  After that
 
     struct  {
         unsigned antialias:1;
-        unsigned showcallouts:1;
         unsigned colorbytes:1;
+        unsigned showcallouts:1;
         HFEditMode editMode:2;
         unsigned editable:1;
         unsigned selectable:1;
         unsigned selectionInProgress:1;
         unsigned shiftExtendSelection:1;
         unsigned commandExtendSelection:1;
+        unsigned livereload:1;
     } _hfflags;
 }
 
@@ -328,25 +329,34 @@ You create an HFController via <tt>[[HFController alloc] init]</tt>.  After that
 - (void)setShouldAntialias:(BOOL)antialias;
 //@}
 
+/*! @name Byte coloring
+ Set and get whether the bytes should be colorized. When enabled, characters have a background color that correlates to their byte values. */
+//@{
+/*! Returns whether characters should be colored. */
+- (BOOL)shouldColorBytes;
+
+/*! Sets whether characters should be colored. */
+- (void)setShouldColorBytes:(BOOL)colorbytes;
+//@}
+
 /*! @name Callouts
- Set and get whether bookmark callouts should be shown/ */
+ Set and get whether bookmark callouts should be shown. */
 //@{
-/*! Returns whether text should be antialiased. */
+/*! Returns whether bookmark callouts should be shown. */
 - (BOOL)shouldShowCallouts;
 
-/*! Sets whether text should be antialiased. */
+/*! Sets whether bookmark callouts should be shown. */
 - (void)setShouldShowCallouts:(BOOL)showcallouts;
 //@}
 
-
-/*! @name Byte coloring
- Set and get whether the bytes should be colorized. When enabled, characters have a background color that correlates to their byte values. */
+/*! @name Live reload
+ Set and get whether unmodified documents should be auto refreshed to their latest on disk state. */
 //@{
-/*! Returns whether characters should be colored. */
-- (BOOL)shouldColorBytes;
+/*! Returns whether live reload should occur. */
+- (BOOL)shouldLiveReload;
 
-/*! Sets whether characters should be colored. */
-- (void)setShouldColorBytes:(BOOL)colorbytes;
+/*! Sets whether live reload should occur. */
+- (void)setShouldLiveReload:(BOOL)livereload;
 //@}
 
 /*! Representer initiated property changes

framework/sources/HFController.m

@@ -129,8 +129,9 @@ - (void)encodeWithCoder:(NSCoder *)coder {
     [coder encodeObject:font forKey:@"HFFont"];
     [coder encodeDouble:lineHeight forKey:@"HFLineHeight"];
     [coder encodeBool:_hfflags.antialias forKey:@"HFAntialias"];
-    [coder encodeBool:_hfflags.showcallouts forKey:@"HFShowCallouts"];
     [coder encodeBool:_hfflags.colorbytes forKey:@"HFColorBytes"];
+    [coder encodeBool:_hfflags.showcallouts forKey:@"HFShowCallouts"];
+    [coder encodeBool:_hfflags.livereload forKey:@"HFLiveReload"];
     [coder encodeInt:_hfflags.editMode forKey:@"HFEditMode"];
     [coder encodeBool:_hfflags.editable forKey:@"HFEditable"];
     [coder encodeBool:_hfflags.selectable forKey:@"HFSelectable"];
@@ -145,8 +146,8 @@ - (id)initWithCoder:(NSCoder *)coder {
     font = [[coder decodeObjectForKey:@"HFFont"] retain];
     lineHeight = (CGFloat)[coder decodeDoubleForKey:@"HFLineHeight"];
     _hfflags.antialias = [coder decodeBoolForKey:@"HFAntialias"];
-    _hfflags.showcallouts = [coder decodeBoolForKey:@"HFShowCallouts"];
     _hfflags.colorbytes = [coder decodeBoolForKey:@"HFColorBytes"];
+    _hfflags.livereload = [coder decodeBoolForKey:@"HFLiveReload"];
 
     if ([coder containsValueForKey:@"HFEditMode"])
         _hfflags.editMode = [coder decodeIntForKey:@"HFEditMode"];
@@ -342,6 +343,18 @@ - (void)setShouldAntialias:(BOOL)antialias {
     }
 }
 
+- (BOOL)shouldColorBytes {
+    return _hfflags.colorbytes;
+}
+
+- (void)setShouldColorBytes:(BOOL)colorbytes {
+    colorbytes = !! colorbytes;
+    if (colorbytes != _hfflags.colorbytes) {
+        _hfflags.colorbytes = colorbytes;
+        [self _addPropertyChangeBits:HFControllerColorBytes];
+    }
+}
+
 - (BOOL)shouldShowCallouts {
     return _hfflags.showcallouts;
 }
@@ -354,20 +367,15 @@ - (void)setShouldShowCallouts:(BOOL)showcallouts {
     }
 }
 
-
-- (BOOL)shouldColorBytes {
-    return _hfflags.colorbytes;
+- (BOOL)shouldLiveReload {
+    return _hfflags.livereload;
 }
 
-- (void)setShouldColorBytes:(BOOL)colorbytes {
-    colorbytes = !! colorbytes;
-    if (colorbytes != _hfflags.colorbytes) {
-        _hfflags.colorbytes = colorbytes;
-        [self _addPropertyChangeBits:HFControllerColorBytes];
-    }
+- (void)setShouldLiveReload:(BOOL)livereload {
+    _hfflags.livereload = !!livereload;
+
 }
 
-
 - (void)setBytesPerColumn:(NSUInteger)val {
     if (val != bytesPerColumn) {
         bytesPerColumn = val;