Create valid xar files

Autoupdate/SUBinaryDeltaApply.m

@@ -186,6 +186,9 @@ BOOL applyBinaryDelta(NSString *source, NSString *destination, NSString *patchFi
         // Don't use -[NSFileManager fileExistsAtPath:] because it will follow symbolic links
         BOOL fileExisted = verbose && [fileManager attributesOfItemAtPath:destinationFilePath error:nil];
         BOOL removedFile = NO;
+
+        // Files that have no property set that we check for will get ignored
+        // This is important because they aren't part of the delta, just part of the directory structure
 
         const char *value;
         if (!xar_prop_get(file, DELETE_KEY, &value) || (!hasExtractKeyAvailable && !xar_prop_get(file, DELETE_THEN_EXTRACT_OLD_KEY, &value))) {

Autoupdate/SUBinaryDeltaCommon.h

@@ -61,7 +61,6 @@ typedef NS_ENUM(uint16_t, SUBinaryDeltaMajorVersion)
 #define LATEST_DELTA_DIFF_MAJOR_VERSION SUBeigeMajorVersion
 
 extern int compareFiles(const FTSENT **a, const FTSENT **b);
-extern NSData *hashOfFileContents(FTSENT *ent);
 extern NSString *hashOfTreeWithVersion(NSString *path, uint16_t majorVersion);
 extern NSString *hashOfTree(NSString *path);
 extern BOOL removeTree(NSString *path);

Autoupdate/SUBinaryDeltaCommon.m

@@ -45,7 +45,7 @@ int latestMinorVersionForMajorVersion(SUBinaryDeltaMajorVersion majorVersion)
         case SUAzureMajorVersion:
             return 1;
         case SUBeigeMajorVersion:
-            return 2;
+            return 3;
     }
     return 0;
 }
@@ -137,15 +137,6 @@ static BOOL _hashOfFileContents(unsigned char *hash, FTSENT *ent)
     return YES;
 }
 
-NSData *hashOfFileContents(FTSENT *ent)
-{
-    unsigned char fileHash[CC_SHA1_DIGEST_LENGTH];
-    if (!_hashOfFileContents(fileHash, ent)) {
-        return nil;
-    }
-    return [NSData dataWithBytes:fileHash length:CC_SHA1_DIGEST_LENGTH];
-}
-
 NSString *hashOfTreeWithVersion(NSString *path, uint16_t majorVersion)
 {
     char pathBuffer[PATH_MAX] = { 0 };

Autoupdate/SUBinaryDeltaCreate.m

@@ -66,25 +66,23 @@ - (void)main
 
 @end
 
-#define INFO_HASH_KEY @"hash"
+#define INFO_PATH_KEY @"path"
 #define INFO_TYPE_KEY @"type"
 #define INFO_PERMISSIONS_KEY @"permissions"
 #define INFO_SIZE_KEY @"size"
 
 static NSDictionary *infoForFile(FTSENT *ent)
 {
-    NSData *hash = hashOfFileContents(ent);
-    if (!hash) {
-        return nil;
-    }
-
     off_t size = (ent->fts_info != FTS_D) ? ent->fts_statp->st_size : 0;
 
     assert(ent->fts_statp != NULL);
 
     mode_t permissions = ent->fts_statp->st_mode & PERMISSION_FLAGS;
 
-    return @{ INFO_HASH_KEY: hash,
+    NSString *path = @(ent->fts_path);
+    assert(path != nil);
+
+    return @{ INFO_PATH_KEY: path != nil ? path : @"",
               INFO_TYPE_KEY: @(ent->fts_info),
               INFO_PERMISSIONS_KEY: @(permissions),
               INFO_SIZE_KEY: @(size) };
@@ -174,12 +172,19 @@ static BOOL shouldSkipDeltaCompression(NSDictionary *originalInfo, NSDictionary
         return YES;
     }
 
-    if ([(NSNumber *)originalInfo[INFO_TYPE_KEY] unsignedShortValue] != [(NSNumber *)newInfo[INFO_TYPE_KEY] unsignedShortValue]) {
+    unsigned short originalInfoType = [(NSNumber *)originalInfo[INFO_TYPE_KEY] unsignedShortValue];
+    unsigned short newInfoType = [(NSNumber *)newInfo[INFO_TYPE_KEY] unsignedShortValue];
+    if (originalInfoType != newInfoType) {
+        // File types are different
         return YES;
     }
 
-    if ([(NSData *)originalInfo[INFO_HASH_KEY] isEqual:(NSData *)newInfo[INFO_HASH_KEY]]) {
-        // this is possible if just the permissions have changed
+    NSString *originalPath = originalInfo[INFO_PATH_KEY];
+    NSString *newPath = newInfo[INFO_PATH_KEY];
+
+    // Skip delta if both entries are directories, or if the files/symlinks are equal in content
+    if (originalInfoType == FTS_D || [[NSFileManager defaultManager] contentsEqualAtPath:originalPath andPath:newPath]) {
+        // this is possible if just the permissions have changed but contents have not
         return YES;
     }
 
@@ -205,11 +210,21 @@ static BOOL shouldSkipExtracting(NSDictionary *originalInfo, NSDictionary *newIn
         return NO;
     }
 
-    if ([(NSNumber *)originalInfo[INFO_TYPE_KEY] unsignedShortValue] != [(NSNumber *)newInfo[INFO_TYPE_KEY] unsignedShortValue]) {
+    unsigned short originalInfoType = [(NSNumber *)originalInfo[INFO_TYPE_KEY] unsignedShortValue];
+    unsigned short newInfoType = [(NSNumber *)newInfo[INFO_TYPE_KEY] unsignedShortValue];
+
+    if (originalInfoType != newInfoType) {
+        // File types are different
         return NO;
     }
 
-    if (![(NSData *)originalInfo[INFO_HASH_KEY] isEqual:(NSData *)newInfo[INFO_HASH_KEY]]) {
+
+    NSString *originalPath = originalInfo[INFO_PATH_KEY];
+    NSString *newPath = newInfo[INFO_PATH_KEY];
+
+    // Don't skip extract if files/symlinks entries are not equal in content
+    // (note if the entries are directories, they are equal)
+    if (originalInfoType != FTS_D && ![[NSFileManager defaultManager] contentsEqualAtPath:originalPath andPath:newPath]) {
         return NO;
     }
 
@@ -233,6 +248,52 @@ static BOOL shouldChangePermissions(NSDictionary *originalInfo, NSDictionary *ne
     return YES;
 }
 
+static xar_file_t _xarAddFile(NSMutableDictionary<NSString *, NSValue *> *fileTable, xar_t x, NSString *relativePath, NSString *filePath)
+{
+    NSArray<NSString *> *rootRelativePathComponents = relativePath.pathComponents;
+    // Relative path must at least have starting "/" component and one more path component
+    if (rootRelativePathComponents.count < 2) {
+        return NULL;
+    }
+
+    NSArray<NSString *> *relativePathComponents = [rootRelativePathComponents subarrayWithRange:NSMakeRange(1, rootRelativePathComponents.count - 1)];
+
+    NSUInteger relativePathComponentsCount = relativePathComponents.count;
+
+    // Build parent files as needed until we get to our final file we want to add
+    // So if we get "Contents/Resources/foo.txt", we will first add "Contents" parent,
+    // then "Resources" parent, then "foo.txt" as the final entry we want to add
+    // We store every file we add into a fileTable for easy referencing
+    // Note if a diff has Contents/Resources/foo/ and Contents/Resources/foo/bar.txt,
+    // due to sorting order we will add the foo directory first and won't end up with
+    // mis-ordering bugs
+    xar_file_t lastParent = NULL;
+    for (NSUInteger componentIndex = 0; componentIndex < relativePathComponentsCount; componentIndex++) {
+        NSArray<NSString *> *subpathComponents = [relativePathComponents subarrayWithRange:NSMakeRange(0, componentIndex + 1)];
+        NSString *subpathKey = [subpathComponents componentsJoinedByString:@"/"];
+
+        xar_file_t cachedFile = [fileTable[subpathKey] pointerValue];
+        if (cachedFile != NULL) {
+            lastParent = cachedFile;
+        } else {
+            xar_file_t newParent;
+
+            BOOL atLastIndex = (componentIndex == relativePathComponentsCount - 1);
+
+            NSString *lastPathComponent = subpathComponents.lastObject;
+            if (atLastIndex && filePath != nil) {
+                newParent = xar_add_frompath(x, lastParent, lastPathComponent.fileSystemRepresentation, filePath.fileSystemRepresentation);
+            } else {
+                newParent = xar_add_frombuffer(x, lastParent, lastPathComponent.fileSystemRepresentation, "", 1);
+            }
+
+            lastParent = newParent;
+            fileTable[subpathKey] = [NSValue valueWithPointer:newParent];
+        }
+    }
+    return lastParent;
+}
+
 BOOL createBinaryDelta(NSString *source, NSString *destination, NSString *patchFile, SUBinaryDeltaMajorVersion majorVersion, BOOL verbose, NSError *__autoreleasing *error)
 {
     assert(source);
@@ -489,11 +550,14 @@ BOOL createBinaryDelta(NSString *source, NSString *destination, NSString *patchF
 
       return originalTreeState[key1] ? NSOrderedAscending : NSOrderedDescending;
     }];
+
+    NSMutableDictionary<NSString *, NSValue *> *fileTable = [NSMutableDictionary dictionary];
+
     for (NSString *key in keys) {
         id value = [newTreeState valueForKey:key];
 
         if ([(NSObject *)value isEqual:[NSNull null]]) {
-            xar_file_t newFile = xar_add_frombuffer(x, 0, [key fileSystemRepresentation], (char *)"", 1);
+            xar_file_t newFile = _xarAddFile(fileTable, x, key, NULL);
             assert(newFile);
             xar_prop_set(newFile, DELETE_KEY, "true");
 
@@ -508,7 +572,7 @@ BOOL createBinaryDelta(NSString *source, NSString *destination, NSString *patchF
         if (shouldSkipDeltaCompression(originalInfo, newInfo)) {
             if (MAJOR_VERSION_IS_AT_LEAST(majorVersion, SUBeigeMajorVersion) && shouldSkipExtracting(originalInfo, newInfo)) {
                 if (shouldChangePermissions(originalInfo, newInfo)) {
-                    xar_file_t newFile = xar_add_frombuffer(x, 0, [key fileSystemRepresentation], (char *)"", 1);
+                    xar_file_t newFile = _xarAddFile(fileTable, x, key, NULL);
                     assert(newFile);
                     xar_prop_set(newFile, MODIFY_PERMISSIONS_KEY, [[NSString stringWithFormat:@"%u", [(NSNumber *)newInfo[INFO_PERMISSIONS_KEY] unsignedShortValue]] UTF8String]);
 
@@ -518,7 +582,7 @@ BOOL createBinaryDelta(NSString *source, NSString *destination, NSString *patchF
                 }
             } else {
                 NSString *path = [destination stringByAppendingPathComponent:key];
-                xar_file_t newFile = xar_add_frompath(x, 0, [key fileSystemRepresentation], [path fileSystemRepresentation]);
+                xar_file_t newFile = _xarAddFile(fileTable, x, key, path);
                 assert(newFile);
 
                 if (shouldDeleteThenExtract(originalInfo, newInfo)) {
@@ -570,7 +634,7 @@ BOOL createBinaryDelta(NSString *source, NSString *destination, NSString *patchF
             fprintf(stderr, "\n🔨  %s %s", VERBOSE_DIFFED, [[operation relativePath] fileSystemRepresentation]);
         }
 
-        xar_file_t newFile = xar_add_frompath(x, 0, [[operation relativePath] fileSystemRepresentation], [resultPath fileSystemRepresentation]);
+        xar_file_t newFile = _xarAddFile(fileTable, x, [operation relativePath], resultPath);
         assert(newFile);
         xar_prop_set(newFile, BINARY_DELTA_KEY, "true");
         unlink([resultPath fileSystemRepresentation]);