InputStream: make Seek() always absolute

Remove the "whence" parameter that is not actually necessary, and only
complicates the InputStream implementations.

src/input/InputStream.cxx

@@ -23,7 +23,6 @@
 #include "util/UriUtil.hxx"
 
 #include <assert.h>
-#include <stdio.h> /* for SEEK_SET */
 
 InputStream::~InputStream()
 {
@@ -75,29 +74,17 @@ InputStream::CheapSeeking() const
 }
 
 bool
-InputStream::Seek(gcc_unused offset_type new_offset, gcc_unused int whence,
+InputStream::Seek(gcc_unused offset_type new_offset,
 		  gcc_unused Error &error)
 {
 	return false;
 }
 
 bool
-InputStream::LockSeek(offset_type _offset, int whence, Error &error)
+InputStream::LockSeek(offset_type _offset, Error &error)
 {
 	const ScopeLock protect(mutex);
-	return Seek(_offset, whence, error);
-}
-
-bool
-InputStream::Rewind(Error &error)
-{
-	return Seek(0, SEEK_SET, error);
-}
-
-bool
-InputStream::LockRewind(Error &error)
-{
-	return LockSeek(0, SEEK_SET, error);
+	return Seek(_offset, error);
 }
 
 Tag *

src/input/InputStream.hxx

@@ -275,22 +275,26 @@ public:
 	 * The caller must lock the mutex.
 	 *
 	 * @param offset the relative offset
-	 * @param whence the base of the seek, one of SEEK_SET, SEEK_CUR, SEEK_END
 	 */
-	virtual bool Seek(offset_type offset, int whence, Error &error);
+	virtual bool Seek(offset_type offset, Error &error);
 
 	/**
 	 * Wrapper for Seek() which locks and unlocks the mutex; the
 	 * caller must not be holding it already.
 	 */
-	bool LockSeek(offset_type offset, int whence, Error &error);
+	bool LockSeek(offset_type offset, Error &error);
 
 	/**
 	 * Rewind to the beginning of the stream.  This is a wrapper
-	 * for Seek(0, SEEK_SET, error).
+	 * for Seek(0, error).
 	 */
-	bool Rewind(Error &error);
-	bool LockRewind(Error &error);
+	bool Rewind(Error &error) {
+		return Seek(0, error);
+	}
+
+	bool LockRewind(Error &error) {
+		return LockSeek(0, error);
+	}
 
 	/**
 	 * Returns true if the stream has reached end-of-file.

src/input/ProxyInputStream.cxx

@@ -63,9 +63,9 @@ ProxyInputStream::Update()
 }
 
 bool
-ProxyInputStream::Seek(offset_type new_offset, int whence, Error &error)
+ProxyInputStream::Seek(offset_type new_offset, Error &error)
 {
-	bool success = input.Seek(new_offset, whence, error);
+	bool success = input.Seek(new_offset, error);
 	CopyAttributes();
 	return success;
 }

src/input/ProxyInputStream.hxx

@@ -45,7 +45,7 @@ public:
 	/* virtual methods from InputStream */
 	bool Check(Error &error) override;
 	void Update() override;
-	bool Seek(offset_type new_offset, int whence, Error &error) override;
+	bool Seek(offset_type new_offset, Error &error) override;
 	bool IsEOF() override;
 	Tag *ReadTag() override;
 	bool IsAvailable() override;

src/input/plugins/CdioParanoiaInputPlugin.cxx

@@ -99,7 +99,7 @@ class CdioParanoiaInputStream final : public InputStream {
 	/* virtual methods from InputStream */
 	bool IsEOF() override;
 	size_t Read(void *ptr, size_t size, Error &error) override;
-	bool Seek(offset_type offset, int whence, Error &error) override;
+	bool Seek(offset_type offset, Error &error) override;
 };
 
 static constexpr Domain cdio_domain("cdio");
@@ -272,21 +272,8 @@ input_cdio_open(const char *uri,
 }
 
 bool
-CdioParanoiaInputStream::Seek(InputPlugin::offset_type new_offset,
-			      int whence, Error &error)
+CdioParanoiaInputStream::Seek(offset_type new_offset, Error &error)
 {
-	/* calculate absolute offset */
-	switch (whence) {
-	case SEEK_SET:
-		break;
-	case SEEK_CUR:
-		new_offset += offset;
-		break;
-	case SEEK_END:
-		new_offset += size;
-		break;
-	}
-
 	if (new_offset < 0 || new_offset > size) {
 		error.Format(cdio_domain, "Invalid offset to seek %ld (%ld)",
 			     (long int)new_offset, (long int)size);

src/input/plugins/CurlInputPlugin.cxx

@@ -175,7 +175,7 @@ struct CurlInputStream final : public InputStream {
 	}
 
 	size_t Read(void *ptr, size_t size, Error &error) override;
-	bool Seek(offset_type offset, int whence, Error &error) override;
+	bool Seek(offset_type offset, Error &error) override;
 };
 
 class CurlMulti;
@@ -887,12 +887,11 @@ CurlInputStream::InitEasy(Error &error)
 }
 
 inline bool
-CurlInputStream::Seek(InputPlugin::offset_type new_offset, int whence,
-		      Error &error)
+CurlInputStream::Seek(offset_type new_offset, Error &error)
 {
 	assert(IsReady());
 
-	if (whence == SEEK_SET && new_offset == offset)
+	if (new_offset == offset)
 		/* no-op */
 		return true;
 
@@ -901,26 +900,6 @@ CurlInputStream::Seek(InputPlugin::offset_type new_offset, int whence,
 
 	/* calculate the absolute offset */
 
-	switch (whence) {
-	case SEEK_SET:
-		break;
-
-	case SEEK_CUR:
-		new_offset += offset;
-		break;
-
-	case SEEK_END:
-		if (size < 0)
-			/* stream size is not known */
-			return false;
-
-		new_offset += size;
-		break;
-
-	default:
-		return false;
-	}
-
 	if (new_offset < 0)
 		return false;
 

src/input/plugins/FfmpegInputPlugin.cxx

@@ -60,7 +60,7 @@ struct FfmpegInputStream final : public InputStream {
 	/* virtual methods from InputStream */
 	bool IsEOF() override;
 	size_t Read(void *ptr, size_t size, Error &error) override;
-	bool Seek(offset_type offset, int whence, Error &error) override;
+	bool Seek(offset_type offset, Error &error) override;
 };
 
 static constexpr Domain ffmpeg_domain("ffmpeg");
@@ -134,9 +134,9 @@ FfmpegInputStream::IsEOF()
 }
 
 bool
-FfmpegInputStream::Seek(offset_type new_offset, int whence, Error &error)
+FfmpegInputStream::Seek(offset_type new_offset, Error &error)
 {
-	int64_t ret = avio_seek(h, new_offset, whence);
+	int64_t ret = avio_seek(h, new_offset, SEEK_SET);
 
 	if (ret >= 0) {
 		eof = false;

src/input/plugins/FileInputPlugin.cxx

@@ -56,7 +56,7 @@ struct FileInputStream final : public InputStream {
 	}
 
 	size_t Read(void *ptr, size_t size, Error &error) override;
-	bool Seek(offset_type offset, int whence, Error &error) override;
+	bool Seek(offset_type offset, Error &error) override;
 };
 
 static InputStream *
@@ -99,11 +99,9 @@ input_file_open(const char *filename,
 }
 
 bool
-FileInputStream::Seek(InputPlugin::offset_type new_offset, int whence,
-		      Error &error)
+FileInputStream::Seek(offset_type new_offset, Error &error)
 {
-	new_offset = (InputPlugin::offset_type)lseek(fd, (off_t)new_offset,
-						     whence);
+	new_offset = (offset_type)lseek(fd, (off_t)new_offset, SEEK_SET);
 	if (new_offset < 0) {
 		error.SetErrno("Failed to seek");
 		return false;

src/input/plugins/NfsInputPlugin.cxx

@@ -61,7 +61,7 @@ public:
 	}
 
 	size_t Read(void *ptr, size_t size, Error &error) override;
-	bool Seek(offset_type offset, int whence, Error &error) override;
+	bool Seek(offset_type offset, Error &error) override;
 };
 
 size_t
@@ -77,10 +77,10 @@ NfsInputStream::Read(void *ptr, size_t read_size, Error &error)
 }
 
 bool
-NfsInputStream::Seek(offset_type new_offset, int whence, Error &error)
+NfsInputStream::Seek(offset_type new_offset, Error &error)
 {
 	uint64_t current_offset;
-	int result = nfs_lseek(ctx, fh, new_offset, whence,
+	int result = nfs_lseek(ctx, fh, new_offset, SEEK_SET,
 			       &current_offset);
 	if (result < 0) {
 		error.SetErrno(-result, "smbc_lseek() failed");

src/input/plugins/RewindInputPlugin.cxx

@@ -64,7 +64,7 @@ public:
 	}
 
 	size_t Read(void *ptr, size_t size, Error &error) override;
-	bool Seek(offset_type offset, int whence, Error &error) override;
+	bool Seek(offset_type offset, Error &error) override;
 
 private:
 	/**
@@ -117,13 +117,12 @@ RewindInputStream::Read(void *ptr, size_t read_size, Error &error)
 }
 
 bool
-RewindInputStream::Seek(offset_type new_offset, int whence,
+RewindInputStream::Seek(offset_type new_offset,
 			Error &error)
 {
 	assert(IsReady());
 
-	if (whence == SEEK_SET && tail > 0 &&
-	    new_offset <= (offset_type)tail) {
+	if (tail > 0 && new_offset <= (offset_type)tail) {
 		/* buffered seek */
 
 		assert(!ReadingFromBuffer() ||
@@ -139,7 +138,7 @@ RewindInputStream::Seek(offset_type new_offset, int whence,
 		   buffered range now */
 		tail = 0;
 
-		return ProxyInputStream::Seek(new_offset, whence, error);
+		return ProxyInputStream::Seek(new_offset, error);
 	}
 }
 

src/input/plugins/SmbclientInputPlugin.cxx

@@ -57,7 +57,7 @@ public:
 	}
 
 	size_t Read(void *ptr, size_t size, Error &error) override;
-	bool Seek(offset_type offset, int whence, Error &error) override;
+	bool Seek(offset_type offset, Error &error) override;
 };
 
 /*
@@ -136,11 +136,10 @@ SmbclientInputStream::Read(void *ptr, size_t read_size, Error &error)
 }
 
 bool
-SmbclientInputStream::Seek(InputStream::offset_type new_offset,
-			   int whence, Error &error)
+SmbclientInputStream::Seek(offset_type new_offset, Error &error)
 {
 	smbclient_mutex.lock();
-	off_t result = smbc_lseek(fd, new_offset, whence);
+	off_t result = smbc_lseek(fd, new_offset, SEEK_SET);
 	smbclient_mutex.unlock();
 	if (result < 0) {
 		error.SetErrno("smbc_lseek() failed");