Ensure input source is open before sending -supportsSeeking (#649)

Author: sbooth

Sources/CSFBAudioEngine/Decoders/SFBAudioDecoder.m

@@ -171,16 +171,17 @@ - (instancetype)initWithInputSource:(SFBInputSource *)inputSource detectContentT
 	NSString *lowercaseExtension = inputSource.url.pathExtension.lowercaseString;
 	NSString *lowercaseMIMEType = mimeTypeHint.lowercaseString;
 
-	// Instead of failing for non-seekable inputs just skip content type detection
-	if(detectContentType && !inputSource.supportsSeeking) {
-		os_log_error(gSFBAudioDecoderLog, "Unable to detect content type for non-seekable input source %{public}@", inputSource);
-		detectContentType = NO;
+	if(detectContentType) {
+		// If the input source can't be opened decoding is destined to fail; give up now
+		if(!inputSource.isOpen && ![inputSource openReturningError:error])
+			return nil;
+		// Instead of failing for non-seekable inputs just skip content type detection
+		if(!inputSource.supportsSeeking) {
+			os_log_error(gSFBAudioDecoderLog, "Unable to detect content type for non-seekable input source %{public}@", inputSource);
+			detectContentType = NO;
+		}
 	}
 
-	// If the input source can't be opened decoding is destined to fail; give up now
-	if(detectContentType && !inputSource.isOpen && ![inputSource openReturningError:error])
-		return nil;
-
 	int score = 10;
 	Class subclass = nil;
 

Sources/CSFBAudioEngine/Decoders/SFBDSDDecoder.m

@@ -171,16 +171,17 @@ - (instancetype)initWithInputSource:(SFBInputSource *)inputSource detectContentT
 	NSString *lowercaseExtension = inputSource.url.pathExtension.lowercaseString;
 	NSString *lowercaseMIMEType = mimeTypeHint.lowercaseString;
 
-	// Instead of failing for non-seekable inputs just skip content type detection
-	if(detectContentType && !inputSource.supportsSeeking) {
-		os_log_error(gSFBDSDDecoderLog, "Unable to detect content type for non-seekable input source %{public}@", inputSource);
-		detectContentType = NO;
+	if(detectContentType) {
+		// If the input source can't be opened decoding is destined to fail; give up now
+		if(!inputSource.isOpen && ![inputSource openReturningError:error])
+			return nil;
+		// Instead of failing for non-seekable inputs just skip content type detection
+		if(!inputSource.supportsSeeking) {
+			os_log_error(gSFBDSDDecoderLog, "Unable to detect content type for non-seekable input source %{public}@", inputSource);
+			detectContentType = NO;
+		}
 	}
 
-	// If the input source can't be opened decoding is destined to fail; give up now
-	if(detectContentType && !inputSource.isOpen && ![inputSource openReturningError:error])
-		return nil;
-
 	int score = 10;
 	Class subclass = nil;
 

Sources/CSFBAudioEngine/Input/SFBFileInputSource.m

@@ -125,7 +125,9 @@ - (BOOL)getLength:(NSInteger *)length error:(NSError **)error
 
 - (BOOL)supportsSeeking
 {
-	return YES;
+	// Regular files are always seekable.
+	// Punt on testing whether ftello() and fseeko() actually work.
+	return S_ISREG(_filestats.st_mode);
 }
 
 - (BOOL)seekToOffset:(NSInteger)offset error:(NSError **)error