305 lines
12 KiB
Objective-C
305 lines
12 KiB
Objective-C
//
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// KBBackspaceUndoManager.m
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// CustomKeyboard
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//
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#import "KBBackspaceUndoManager.h"
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#import "KBResponderUtils.h"
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#import "KBInputBufferManager.h"
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NSNotificationName const KBBackspaceUndoStateDidChangeNotification = @"KBBackspaceUndoStateDidChangeNotification";
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#if DEBUG
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static NSString *KBLogString(NSString *tag, NSString *text) {
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NSString *safeTag = tag ?: @"";
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NSString *safeText = text ?: @"";
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if (safeText.length <= 2000) {
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return [NSString stringWithFormat:@"[%@] len=%lu text=%@", safeTag, (unsigned long)safeText.length, safeText];
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}
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NSString *head = [safeText substringToIndex:800];
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NSString *tail = [safeText substringFromIndex:safeText.length - 800];
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return [NSString stringWithFormat:@"[%@] len=%lu head=%@ ... tail=%@", safeTag, (unsigned long)safeText.length, head, tail];
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}
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#define KB_UNDO_LOG(tag, text) NSLog(@"%@", KBLogString((tag), (text)))
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#else
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#define KB_UNDO_LOG(tag, text) do {} while(0)
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#endif
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typedef NS_ENUM(NSInteger, KBUndoSnapshotSource) {
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KBUndoSnapshotSourceNone = 0,
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KBUndoSnapshotSourceDeletionSnapshot,
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KBUndoSnapshotSourceClear
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};
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@interface KBBackspaceUndoManager ()
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@property (nonatomic, copy) NSString *undoText;
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@property (nonatomic, assign) NSInteger undoAfterLength;
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@property (nonatomic, assign) BOOL hasUndo;
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@property (nonatomic, assign) KBUndoSnapshotSource snapshotSource;
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@property (nonatomic, strong) NSMutableArray<NSString *> *undoDeletedPieces;
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@end
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@implementation KBBackspaceUndoManager
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+ (instancetype)shared {
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static KBBackspaceUndoManager *mgr = nil;
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static dispatch_once_t onceToken;
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dispatch_once(&onceToken, ^{
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mgr = [[KBBackspaceUndoManager alloc] init];
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});
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return mgr;
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}
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- (instancetype)init {
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if (self = [super init]) {
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_undoText = @"";
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_undoAfterLength = 0;
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_snapshotSource = KBUndoSnapshotSourceNone;
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_undoDeletedPieces = [NSMutableArray array];
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}
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return self;
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}
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- (void)captureAndDeleteBackwardFromProxy:(id<UITextDocumentProxy>)proxy count:(NSUInteger)count {
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if (!proxy || count == 0) { return; }
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NSString *selected = proxy.selectedText ?: @"";
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NSString *ctxBefore = proxy.documentContextBeforeInput ?: @"";
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NSString *ctxAfter = proxy.documentContextAfterInput ?: @"";
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NSUInteger ctxLen = ctxBefore.length + ctxAfter.length;
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BOOL isSelectAllLike = (selected.length > 0 &&
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(ctxLen == 0 || selected.length >= MAX((NSUInteger)40, ctxLen * 2)));
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if (isSelectAllLike) {
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// “全选删除”在微信/QQ中通常拿不到可靠的全文，因此禁用撤销，避免插回错误/不完整内容。
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if (self.hasUndo) {
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[self registerNonClearAction];
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}
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#if DEBUG
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KB_UNDO_LOG(@"captureAndDelete/selectAllDisableUndo", selected);
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#endif
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[proxy deleteBackward];
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[[KBInputBufferManager shared] resetWithText:@""];
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return;
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}
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if (!self.hasUndo) {
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[self.undoDeletedPieces removeAllObjects];
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self.undoText = @"";
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self.undoAfterLength = 0;
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self.snapshotSource = KBUndoSnapshotSourceDeletionSnapshot;
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[self kb_updateHasUndo:YES];
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}
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BOOL didAppend = NO;
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NSString *lastObservedBefore = nil;
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for (NSUInteger i = 0; i < count; i++) {
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NSString *before = proxy.documentContextBeforeInput ?: @"";
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if (before.length > 0) {
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// 若宿主在同一 runloop 内不更新 context，则跳过记录，避免把同一个字符重复记录成“多句”。
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if (lastObservedBefore && [before isEqualToString:lastObservedBefore]) {
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// still delete, but don't record
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} else {
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NSString *piece = [self kb_lastComposedCharacterFromString:before];
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if (piece.length > 0) {
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[self.undoDeletedPieces addObject:piece];
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didAppend = YES;
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}
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lastObservedBefore = before;
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}
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}
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[proxy deleteBackward];
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}
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#if DEBUG
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if (didAppend) {
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NSUInteger piecesCount = self.undoDeletedPieces.count;
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if (piecesCount <= 20) {
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KB_UNDO_LOG(@"captureAndDelete/undoInsertTextNow", [self kb_buildUndoInsertTextFromPieces]);
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} else if (piecesCount % 50 == 0) {
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NSString *lastPiece = self.undoDeletedPieces.lastObject ?: @"";
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NSLog(@"[captureAndDelete/undoPieces] pieces=%lu lastPiece=%@",
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(unsigned long)piecesCount,
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lastPiece);
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}
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}
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#endif
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}
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- (void)recordDeletionSnapshotBefore:(NSString *)before after:(NSString *)after {
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if (self.hasUndo) { return; }
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NSString *pending = [KBInputBufferManager shared].pendingClearSnapshot;
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NSString *manual = [KBInputBufferManager shared].manualSnapshot;
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NSString *fallbackText = (pending.length > 0) ? pending : ((manual.length > 0) ? manual : [KBInputBufferManager shared].liveText);
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if (fallbackText.length > 0) {
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self.undoText = fallbackText;
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self.undoAfterLength = 0;
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self.snapshotSource = KBUndoSnapshotSourceDeletionSnapshot;
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KB_UNDO_LOG(@"recordDeletionSnapshot/fallback", self.undoText);
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[self kb_updateHasUndo:YES];
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return;
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}
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NSString *safeBefore = before ?: @"";
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NSString *safeAfter = after ?: @"";
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NSString *full = [safeBefore stringByAppendingString:safeAfter];
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if (full.length == 0) { return; }
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self.undoText = full;
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self.undoAfterLength = (NSInteger)safeAfter.length;
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self.snapshotSource = KBUndoSnapshotSourceDeletionSnapshot;
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KB_UNDO_LOG(@"recordDeletionSnapshot/context", self.undoText);
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[self kb_updateHasUndo:YES];
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}
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- (void)recordClearWithContextBefore:(NSString *)before after:(NSString *)after {
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NSString *pending = [KBInputBufferManager shared].pendingClearSnapshot;
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NSString *manual = [KBInputBufferManager shared].manualSnapshot;
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NSString *fallbackText = (pending.length > 0) ? pending : ((manual.length > 0) ? manual : [KBInputBufferManager shared].liveText);
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NSString *safeBefore = before ?: @"";
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NSString *safeAfter = after ?: @"";
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NSString *contextText = [[safeBefore stringByAppendingString:safeAfter] copy];
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NSString *candidate = (fallbackText.length > 0) ? fallbackText : contextText;
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NSInteger candidateAfterLen = (fallbackText.length > 0) ? 0 : (NSInteger)safeAfter.length;
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if (candidate.length == 0) { return; }
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KB_UNDO_LOG(@"recordClear/candidate", candidate);
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if (self.undoText.length > 0) {
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if (self.snapshotSource == KBUndoSnapshotSourceClear) {
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KB_UNDO_LOG(@"recordClear/ignored(alreadyClear)", self.undoText);
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[self kb_updateHasUndo:YES];
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return;
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}
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if (self.snapshotSource == KBUndoSnapshotSourceDeletionSnapshot) {
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if (candidate.length > self.undoText.length) {
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self.undoText = candidate;
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self.undoAfterLength = candidateAfterLen;
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KB_UNDO_LOG(@"recordClear/upgradedFromDeletion", self.undoText);
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} else {
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KB_UNDO_LOG(@"recordClear/keepDeletionSnapshot", self.undoText);
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}
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self.snapshotSource = KBUndoSnapshotSourceClear;
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[self kb_updateHasUndo:YES];
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return;
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}
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}
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self.undoText = candidate;
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self.undoAfterLength = candidateAfterLen;
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self.snapshotSource = KBUndoSnapshotSourceClear;
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KB_UNDO_LOG(@"recordClear/set", self.undoText);
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[self kb_updateHasUndo:YES];
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}
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- (void)performUndoFromResponder:(UIResponder *)responder {
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if (!self.hasUndo) { return; }
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UIInputViewController *ivc = KBFindInputViewController(responder);
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if (!ivc) { return; }
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id<UITextDocumentProxy> proxy = ivc.textDocumentProxy;
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NSString *curBefore = proxy.documentContextBeforeInput ?: @"";
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NSString *curAfter = proxy.documentContextAfterInput ?: @"";
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KB_UNDO_LOG(@"performUndo/currentBefore", curBefore);
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KB_UNDO_LOG(@"performUndo/currentAfter", curAfter);
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NSString *insertText = [self kb_buildUndoInsertTextFromPieces];
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if (insertText.length > 0) {
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KB_UNDO_LOG(@"performUndo/insertDeletedText", insertText);
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[proxy insertText:insertText];
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[[KBInputBufferManager shared] appendText:insertText];
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} else if (self.undoText.length > 0) {
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KB_UNDO_LOG(@"performUndo/fallbackUndoText", self.undoText);
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[self kb_clearAllTextForProxy:proxy];
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[proxy insertText:self.undoText];
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if (self.undoAfterLength > 0 &&
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[proxy respondsToSelector:@selector(adjustTextPositionByCharacterOffset:)]) {
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[proxy adjustTextPositionByCharacterOffset:-self.undoAfterLength];
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}
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[[KBInputBufferManager shared] resetWithText:self.undoText];
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} else {
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return;
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}
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self.undoText = @"";
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self.undoAfterLength = 0;
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self.snapshotSource = KBUndoSnapshotSourceNone;
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[self.undoDeletedPieces removeAllObjects];
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[self kb_updateHasUndo:NO];
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}
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- (void)registerNonClearAction {
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if (!self.hasUndo) { return; }
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if (self.undoText.length > 0) {
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KB_UNDO_LOG(@"registerNonClearAction/clearUndoText", self.undoText);
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}
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if (self.undoDeletedPieces.count > 0) {
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KB_UNDO_LOG(@"registerNonClearAction/clearDeletedPieces", [self kb_buildUndoInsertTextFromPieces]);
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}
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self.undoText = @"";
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self.undoAfterLength = 0;
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self.snapshotSource = KBUndoSnapshotSourceNone;
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[self.undoDeletedPieces removeAllObjects];
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[self kb_updateHasUndo:NO];
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}
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#pragma mark - Helpers
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- (void)kb_updateHasUndo:(BOOL)hasUndo {
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if (self.hasUndo == hasUndo) { return; }
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self.hasUndo = hasUndo;
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[[NSNotificationCenter defaultCenter] postNotificationName:KBBackspaceUndoStateDidChangeNotification object:self];
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}
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- (NSString *)kb_lastComposedCharacterFromString:(NSString *)text {
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if (text.length == 0) { return @""; }
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__block NSString *last = @"";
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[text enumerateSubstringsInRange:NSMakeRange(0, text.length)
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options:NSStringEnumerationByComposedCharacterSequences | NSStringEnumerationReverse
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usingBlock:^(NSString *substring, __unused NSRange substringRange, __unused NSRange enclosingRange, BOOL *stop) {
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last = substring ?: @"";
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*stop = YES;
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}];
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return last ?: @"";
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}
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- (NSString *)kb_buildUndoInsertTextFromPieces {
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if (self.undoDeletedPieces.count == 0) { return @""; }
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NSMutableString *result = [NSMutableString string];
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for (NSInteger i = (NSInteger)self.undoDeletedPieces.count - 1; i >= 0; i--) {
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NSString *piece = self.undoDeletedPieces[(NSUInteger)i] ?: @"";
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if (piece.length == 0) { continue; }
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[result appendString:piece];
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}
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return result;
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}
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static const NSInteger kKBUndoClearMaxRounds = 200;
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- (void)kb_clearAllTextForProxy:(id<UITextDocumentProxy>)proxy {
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if (!proxy) { return; }
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if ([proxy respondsToSelector:@selector(adjustTextPositionByCharacterOffset:)]) {
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NSInteger guard = 0;
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NSString *contextAfter = proxy.documentContextAfterInput ?: @"";
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while (contextAfter.length > 0 && guard < kKBUndoClearMaxRounds) {
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NSInteger offset = (NSInteger)contextAfter.length;
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[proxy adjustTextPositionByCharacterOffset:offset];
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for (NSUInteger i = 0; i < contextAfter.length; i++) {
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[proxy deleteBackward];
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}
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guard += 1;
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contextAfter = proxy.documentContextAfterInput ?: @"";
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}
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}
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NSInteger guard = 0;
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NSString *contextBefore = proxy.documentContextBeforeInput ?: @"";
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while (contextBefore.length > 0 && guard < kKBUndoClearMaxRounds) {
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for (NSUInteger i = 0; i < contextBefore.length; i++) {
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[proxy deleteBackward];
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}
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guard += 1;
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contextBefore = proxy.documentContextBeforeInput ?: @"";
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}
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}
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@end
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