Merge branch 'v0.18.x' into v0.19.x

18 files changed, 110 insertions, 51 deletions

diff --git a/src/Compiler.h b/src/Compiler.h
index 44a87c7ba..fea971526 100644
--- a/src/Compiler.h
+++ b/src/Compiler.h
@@ -20,33 +20,45 @@
 #ifndef COMPILER_H
 #define COMPILER_H
 
-#define GCC_CHECK_VERSION(major, minor) \
-  (defined(__GNUC__) &&                                                 \
-   (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor))))
+#define GCC_MAKE_VERSION(major, minor, patchlevel) ((major) * 10000 + (minor) * 100 + patchlevel)
 
 #ifdef __GNUC__
-#define GCC_VERSION (__GNUC__ * 10000 \
-                     + __GNUC_MINOR__ * 100 \
-                     + __GNUC_PATCHLEVEL__)
+#define GCC_VERSION GCC_MAKE_VERSION(__GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__)
 #else
 #define GCC_VERSION 0
 #endif
 
+#define GCC_CHECK_VERSION(major, minor) \
+	(defined(__GNUC__) && GCC_VERSION >= GCC_MAKE_VERSION(major, minor, 0))
+
+/**
+ * Are we building with gcc (not clang or any other compiler) and a
+ * version older than the specified one?
+ */
+#define GCC_OLDER_THAN(major, minor) \
+	(defined(__GNUC__) && !defined(__clang__) && \
+	 GCC_VERSION < GCC_MAKE_VERSION(major, minor, 0))
+
 #ifdef __clang__
-#  define CLANG_VERSION (__clang_major__ * 10000 \
-			 + __clang_minor__ * 100 \
-			 + __clang_patchlevel__)
+#  define CLANG_VERSION GCC_MAKE_VERSION(__clang_major__, __clang_minor__, __clang_patchlevel__)
 #  if __clang_major__ < 3
 #    error Sorry, your clang version is too old.  You need at least version 3.1.
 #  endif
 #elif defined(__GNUC__)
-#  if !GCC_CHECK_VERSION(4,6)
+#  if GCC_OLDER_THAN(4,6)
 #    error Sorry, your gcc version is too old.  You need at least version 4.6.
 #  endif
 #else
 #  warning Untested compiler.  Use at your own risk!
 #endif
 
+/**
+ * Are we building with the specified version of clang or newer?
+ */
+#define CLANG_CHECK_VERSION(major, minor) \
+	(defined(__clang__) && \
+	 CLANG_VERSION >= GCC_MAKE_VERSION(major, minor, 0))
+
 #if GCC_CHECK_VERSION(4,0)
 
 /* GCC 4.x */
@@ -141,7 +153,7 @@
 #if defined(__cplusplus)
 
 /* support for C++11 "override" was added in gcc 4.7 */
-#if !defined(__clang__) && !GCC_CHECK_VERSION(4,7)
+#if GCC_OLDER_THAN(4,7)
 #define override
 #define final
 #endif
diff --git a/src/SongFilter.cxx b/src/SongFilter.cxx
index 794cb9208..dc0a63df3 100644
--- a/src/SongFilter.cxx
+++ b/src/SongFilter.cxx
@@ -77,7 +77,10 @@ SongFilter::Item::Item(unsigned _tag, time_t _time)
 bool
 SongFilter::Item::StringMatch(const char *s) const
 {
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(s != nullptr);
+#endif
 
 	if (fold_case) {
 		const std::string folded = IcuCaseFold(s);
diff --git a/src/db/plugins/ProxyDatabasePlugin.cxx b/src/db/plugins/ProxyDatabasePlugin.cxx
index fba72210d..5fd224bb5 100644
--- a/src/db/plugins/ProxyDatabasePlugin.cxx
+++ b/src/db/plugins/ProxyDatabasePlugin.cxx
@@ -103,7 +103,7 @@ public:
 	virtual void Close() override;
 	virtual const LightSong *GetSong(const char *uri_utf8,
 				     Error &error) const override;
-	virtual void ReturnSong(const LightSong *song) const;
+	void ReturnSong(const LightSong *song) const override;
 
 	virtual bool Visit(const DatabaseSelection &selection,
 			   VisitDirectory visit_directory,
@@ -731,7 +731,7 @@ ProxyDatabase::Visit(const DatabaseSelection &selection,
 {
 	// TODO: eliminate the const_cast
 	if (!const_cast<ProxyDatabase *>(this)->EnsureConnected(error))
-		return nullptr;
+		return false;
 
 	if (!visit_directory && !visit_playlist && selection.recursive &&
 	    (ServerSupportsSearchBase(connection)
@@ -757,7 +757,7 @@ ProxyDatabase::VisitUniqueTags(const DatabaseSelection &selection,
 {
 	// TODO: eliminate the const_cast
 	if (!const_cast<ProxyDatabase *>(this)->EnsureConnected(error))
-		return nullptr;
+		return false;
 
 	enum mpd_tag_type tag_type2 = Convert(tag_type);
 	if (tag_type2 == MPD_TAG_COUNT) {
@@ -810,7 +810,7 @@ ProxyDatabase::GetStats(const DatabaseSelection &selection,
 
 	// TODO: eliminate the const_cast
 	if (!const_cast<ProxyDatabase *>(this)->EnsureConnected(error))
-		return nullptr;
+		return false;
 
 	struct mpd_stats *stats2 =
 		mpd_run_stats(connection);
diff --git a/src/db/plugins/simple/SimpleDatabasePlugin.hxx b/src/db/plugins/simple/SimpleDatabasePlugin.hxx
index 7ba71e272..d82225f8c 100644
--- a/src/db/plugins/simple/SimpleDatabasePlugin.hxx
+++ b/src/db/plugins/simple/SimpleDatabasePlugin.hxx
@@ -110,9 +110,9 @@ public:
 	virtual bool Open(Error &error) override;
 	virtual void Close() override;
 
-	virtual const LightSong *GetSong(const char *uri_utf8,
-					 Error &error) const override;
-	virtual void ReturnSong(const LightSong *song) const;
+	const LightSong *GetSong(const char *uri_utf8,
+				 Error &error) const override;
+	void ReturnSong(const LightSong *song) const override;
 
 	virtual bool Visit(const DatabaseSelection &selection,
 			   VisitDirectory visit_directory,
diff --git a/src/decoder/DecoderPlugin.cxx b/src/decoder/DecoderPlugin.cxx
index 3be812c3b..a0722c348 100644
--- a/src/decoder/DecoderPlugin.cxx
+++ b/src/decoder/DecoderPlugin.cxx
@@ -26,7 +26,10 @@
 bool
 DecoderPlugin::SupportsSuffix(const char *suffix) const
 {
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(suffix != nullptr);
+#endif
 
 	return suffixes != nullptr && string_array_contains(suffixes, suffix);
 
@@ -35,7 +38,10 @@ DecoderPlugin::SupportsSuffix(const char *suffix) const
 bool
 DecoderPlugin::SupportsMimeType(const char *mime_type) const
 {
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(mime_type != nullptr);
+#endif
 
 	return mime_types != nullptr &&
 		string_array_contains(mime_types, mime_type);
diff --git a/src/filter/plugins/ChainFilterPlugin.cxx b/src/filter/plugins/ChainFilterPlugin.cxx
index 7342beb14..4aeee69af 100644
--- a/src/filter/plugins/ChainFilterPlugin.cxx
+++ b/src/filter/plugins/ChainFilterPlugin.cxx
@@ -53,10 +53,11 @@ public:
 		children.emplace_back(name, filter);
 	}
 
-	virtual AudioFormat Open(AudioFormat &af, Error &error) override;
-	virtual void Close();
-	virtual ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-					    Error &error);
+	/* virtual methods from class Filter */
+	AudioFormat Open(AudioFormat &af, Error &error) override;
+	void Close() override;
+	ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
+					    Error &error) override;
 
 private:
 	/**
diff --git a/src/filter/plugins/NormalizeFilterPlugin.cxx b/src/filter/plugins/NormalizeFilterPlugin.cxx
index a69df2b81..372ab53ac 100644
--- a/src/filter/plugins/NormalizeFilterPlugin.cxx
+++ b/src/filter/plugins/NormalizeFilterPlugin.cxx
@@ -34,10 +34,11 @@ class NormalizeFilter final : public Filter {
 	PcmBuffer buffer;
 
 public:
-	virtual AudioFormat Open(AudioFormat &af, Error &error) override;
-	virtual void Close();
-	virtual ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-					    Error &error) override;
+	/* virtual methods from class Filter */
+	AudioFormat Open(AudioFormat &af, Error &error) override;
+	void Close() override;
+	ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
+				    Error &error) override;
 };
 
 static Filter *
diff --git a/src/filter/plugins/ReplayGainFilterPlugin.cxx b/src/filter/plugins/ReplayGainFilterPlugin.cxx
index 651352ac9..f76e48e37 100644
--- a/src/filter/plugins/ReplayGainFilterPlugin.cxx
+++ b/src/filter/plugins/ReplayGainFilterPlugin.cxx
@@ -112,10 +112,11 @@ public:
 	 */
 	void Update();
 
-	virtual AudioFormat Open(AudioFormat &af, Error &error) override;
-	virtual void Close();
-	virtual ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-					    Error &error) override;
+	/* virtual methods from class Filter */
+	AudioFormat Open(AudioFormat &af, Error &error) override;
+	void Close() override;
+	ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
+				    Error &error) override;
 };
 
 void
diff --git a/src/filter/plugins/RouteFilterPlugin.cxx b/src/filter/plugins/RouteFilterPlugin.cxx
index a252af97d..4094119f2 100644
--- a/src/filter/plugins/RouteFilterPlugin.cxx
+++ b/src/filter/plugins/RouteFilterPlugin.cxx
@@ -120,10 +120,11 @@ public:
 	 */
 	bool Configure(const config_param &param, Error &error);
 
-	virtual AudioFormat Open(AudioFormat &af, Error &error) override;
-	virtual void Close();
-	virtual ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-					    Error &error) override;
+	/* virtual methods from class Filter */
+	AudioFormat Open(AudioFormat &af, Error &error) override;
+	void Close() override;
+	ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
+				    Error &error) override;
 };
 
 bool
diff --git a/src/filter/plugins/VolumeFilterPlugin.cxx b/src/filter/plugins/VolumeFilterPlugin.cxx
index 7b6ccc51e..17e061476 100644
--- a/src/filter/plugins/VolumeFilterPlugin.cxx
+++ b/src/filter/plugins/VolumeFilterPlugin.cxx
@@ -43,10 +43,11 @@ public:
 		pv.SetVolume(_volume);
 	}
 
-	virtual AudioFormat Open(AudioFormat &af, Error &error) override;
-	virtual void Close();
-	virtual ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
-					    Error &error) override;
+	/* virtual methods from class Filter */
+	AudioFormat Open(AudioFormat &af, Error &error) override;
+	void Close() override;
+	ConstBuffer<void> FilterPCM(ConstBuffer<void> src,
+				    Error &error) override;
 };
 
 static constexpr Domain volume_domain("pcm_volume");
diff --git a/src/fs/Charset.cxx b/src/fs/Charset.cxx
index abf4d8287..c634c9340 100644
--- a/src/fs/Charset.cxx
+++ b/src/fs/Charset.cxx
@@ -103,7 +103,10 @@ static inline void FixSeparators(std::string &s)
 std::string
 PathToUTF8(const char *path_fs)
 {
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(path_fs != nullptr);
+#endif
 
 #ifdef HAVE_GLIB
 	if (fs_charset.empty()) {
@@ -144,7 +147,10 @@ PathToUTF8(const char *path_fs)
 char *
 PathFromUTF8(const char *path_utf8)
 {
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(path_utf8 != nullptr);
+#endif
 
 	if (fs_charset.empty())
 		return g_strdup(path_utf8);
diff --git a/src/fs/Traits.cxx b/src/fs/Traits.cxx
index d62987087..166b31f4e 100644
--- a/src/fs/Traits.cxx
+++ b/src/fs/Traits.cxx
@@ -52,7 +52,10 @@ template<typename Traits>
 typename Traits::const_pointer
 GetBasePathImpl(typename Traits::const_pointer p)
 {
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(p != nullptr);
+#endif
 
 	typename Traits::const_pointer sep = Traits::FindLastSeparator(p);
 	return sep != nullptr
@@ -64,7 +67,10 @@ template<typename Traits>
 typename Traits::string
 GetParentPathImpl(typename Traits::const_pointer p)
 {
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(p != nullptr);
+#endif
 
 	typename Traits::const_pointer sep = Traits::FindLastSeparator(p);
 	if (sep == nullptr)
diff --git a/src/input/InputStream.cxx b/src/input/InputStream.cxx
index f5efe8ef1..44f726a62 100644
--- a/src/input/InputStream.cxx
+++ b/src/input/InputStream.cxx
@@ -122,7 +122,10 @@ InputStream::IsAvailable()
 size_t
 InputStream::LockRead(void *ptr, size_t _size, Error &error)
 {
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(ptr != nullptr);
+#endif
 	assert(_size > 0);
 
 	const ScopeLock protect(mutex);
diff --git a/src/output/plugins/ShoutOutputPlugin.cxx b/src/output/plugins/ShoutOutputPlugin.cxx
index 0341e1cf7..b51f7ed82 100644
--- a/src/output/plugins/ShoutOutputPlugin.cxx
+++ b/src/output/plugins/ShoutOutputPlugin.cxx
@@ -109,7 +109,7 @@ ShoutOutput::Configure(const config_param &param, Error &error)
 	if (!audio_format.IsFullyDefined()) {
 		error.Set(config_domain,
 			  "Need full audio format specification");
-		return nullptr;
+		return false;
 	}
 
 	const char *host = require_block_string(param, "host");
diff --git a/src/tag/TagBuilder.cxx b/src/tag/TagBuilder.cxx
index c9ebcd654..93518f6e9 100644
--- a/src/tag/TagBuilder.cxx
+++ b/src/tag/TagBuilder.cxx
@@ -182,7 +182,10 @@ TagBuilder::Complement(const Tag &other)
 inline void
 TagBuilder::AddItemInternal(TagType type, const char *value, size_t length)
 {
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(value != nullptr);
+#endif
 	assert(length > 0);
 
 	auto f = FixTagString(value, length);
@@ -203,7 +206,10 @@ TagBuilder::AddItemInternal(TagType type, const char *value, size_t length)
 void
 TagBuilder::AddItem(TagType type, const char *value, size_t length)
 {
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(value != nullptr);
+#endif
 
 	if (length == 0 || ignore_tag_items[type])
 		return;
@@ -214,7 +220,10 @@ TagBuilder::AddItem(TagType type, const char *value, size_t length)
 void
 TagBuilder::AddItem(TagType type, const char *value)
 {
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(value != nullptr);
+#endif
 
 	AddItem(type, value, strlen(value));
 }
diff --git a/src/util/ASCII.hxx b/src/util/ASCII.hxx
index 19a18a1bb..9f7147338 100644
--- a/src/util/ASCII.hxx
+++ b/src/util/ASCII.hxx
@@ -43,24 +43,30 @@ gcc_pure gcc_nonnull_all
 static inline bool
 StringEqualsCaseASCII(const char *a, const char *b)
 {
-  assert(a != nullptr);
-  assert(b != nullptr);
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
+	assert(a != nullptr);
+	assert(b != nullptr);
+#endif
 
-  /* note: strcasecmp() depends on the locale, but for ASCII-only
-     strings, it's safe to use */
-  return strcasecmp(a, b) == 0;
+	/* note: strcasecmp() depends on the locale, but for ASCII-only
+	   strings, it's safe to use */
+	return strcasecmp(a, b) == 0;
 }
 
 gcc_pure gcc_nonnull_all
 static inline bool
 StringEqualsCaseASCII(const char *a, const char *b, size_t n)
 {
-  assert(a != nullptr);
-  assert(b != nullptr);
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
+	assert(a != nullptr);
+	assert(b != nullptr);
+#endif
 
-  /* note: strcasecmp() depends on the locale, but for ASCII-only
-     strings, it's safe to use */
-  return strncasecmp(a, b, n) == 0;
+	/* note: strcasecmp() depends on the locale, but for ASCII-only
+	   strings, it's safe to use */
+	return strncasecmp(a, b, n) == 0;
 }
 
 #endif
diff --git a/src/util/Manual.hxx b/src/util/Manual.hxx
index baab0a555..75cffac06 100644
--- a/src/util/Manual.hxx
+++ b/src/util/Manual.hxx
@@ -35,7 +35,7 @@
 #include <new>
 #include <utility>
 
-#if !defined(__clang__) && __GNUC__ && !GCC_CHECK_VERSION(4,8)
+#if GCC_OLDER_THAN(4,8)
 #include <type_traits>
 #endif
 
@@ -54,7 +54,7 @@
  */
 template<class T>
 class Manual {
-#if !defined(__clang__) && __GNUC__ && !GCC_CHECK_VERSION(4,8)
+#if GCC_OLDER_THAN(4,8)
 	/* no alignas() on gcc < 4.8: apply worst-case fallback */
 	__attribute__((aligned(8)))
 #else
diff --git a/src/util/UriUtil.cxx b/src/util/UriUtil.cxx
index 62977e91b..54d0ded77 100644
--- a/src/util/UriUtil.cxx
+++ b/src/util/UriUtil.cxx
@@ -140,8 +140,11 @@ uri_remove_auth(const char *uri)
 bool
 uri_is_child(const char *parent, const char *child)
 {
+#if !CLANG_CHECK_VERSION(3,6)
+	/* disabled on clang due to -Wtautological-pointer-compare */
 	assert(parent != nullptr);
 	assert(child != nullptr);
+#endif
 
 	const size_t parent_length = strlen(parent);
 	return memcmp(parent, child, parent_length) == 0 &&