fs/io/GzipOutputStream: use C++ exceptions in constructor

Makefile.am

@@ -605,6 +605,7 @@ libfs_a_CPPFLAGS = $(AM_CPPFLAGS) $(ZLIB_CFLAGS)
 if ENABLE_ZLIB
 libfs_a_SOURCES += \
 	src/lib/zlib/Domain.cxx src/lib/zlib/Domain.hxx \
+	src/lib/zlib/Error.cxx src/lib/zlib/Error.hxx \
 	src/fs/io/GunzipReader.cxx src/fs/io/GunzipReader.hxx \
 	src/fs/io/AutoGunzipReader.cxx src/fs/io/AutoGunzipReader.hxx \
 	src/fs/io/GzipOutputStream.cxx src/fs/io/GzipOutputStream.hxx
@@ -1759,7 +1760,8 @@ noinst_PROGRAMS += test/run_gzip test/run_gunzip
 test_run_gzip_LDADD = \
 	libutil.a \
 	$(FS_LIBS)
-test_run_gzip_SOURCES = test/run_gzip.cxx
+test_run_gzip_SOURCES = test/run_gzip.cxx \
+	src/Log.cxx src/LogBackend.cxx
 
 test_run_gunzip_SOURCES = test/run_gunzip.cxx \
 	src/Log.cxx src/LogBackend.cxx

src/db/plugins/simple/SimpleDatabasePlugin.cxx

@@ -386,10 +386,7 @@ SimpleDatabase::Save(Error &error)
 #ifdef ENABLE_ZLIB
 	std::unique_ptr<GzipOutputStream> gzip;
 	if (compress) {
-		gzip.reset(new GzipOutputStream(*os, error));
-		if (!gzip->IsDefined())
-			return false;
-
+		gzip.reset(new GzipOutputStream(*os));
 		os = gzip.get();
 	}
 #endif

src/fs/io/GzipOutputStream.cxx

@@ -20,10 +20,10 @@
 #include "config.h"
 #include "GzipOutputStream.hxx"
 #include "lib/zlib/Domain.hxx"
+#include "lib/zlib/Error.hxx"
 #include "util/Error.hxx"
-#include "util/Domain.hxx"
 
-GzipOutputStream::GzipOutputStream(OutputStream &_next, Error &error)
+GzipOutputStream::GzipOutputStream(OutputStream &_next) throw(ZlibError)
 	:next(_next)
 {
 	z.next_in = nullptr;
@@ -38,16 +38,13 @@ GzipOutputStream::GzipOutputStream(OutputStream &_next, Error &error)
 	int result = deflateInit2(&z, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
 				  windowBits | gzip_encoding,
 				  8, Z_DEFAULT_STRATEGY);
-	if (result != Z_OK) {
-		z.opaque = this;
-		error.Set(zlib_domain, result, zError(result));
-	}
+	if (result != Z_OK)
+		throw ZlibError(result);
 }
 
 GzipOutputStream::~GzipOutputStream()
 {
-	if (IsDefined())
-		deflateEnd(&z);
+	deflateEnd(&z);
 }
 
 bool

src/fs/io/GzipOutputStream.hxx

@@ -22,13 +22,13 @@
 
 #include "check.h"
 #include "OutputStream.hxx"
+#include "lib/zlib/Error.hxx"
 #include "Compiler.h"
 
 #include <assert.h>
 #include <zlib.h>
 
 class Error;
-class Domain;
 
 /**
  * A filter that compresses data written to it using zlib, forwarding
@@ -43,21 +43,12 @@ class GzipOutputStream final : public OutputStream {
 
 public:
 	/**
-	 * Construct the filter.  Call IsDefined() to check whether
-	 * the constructor has succeeded.  If not, #error will hold
-	 * information about the failure.
+	 * Construct the filter.
 	 */
-	GzipOutputStream(OutputStream &_next, Error &error);
+	GzipOutputStream(OutputStream &_next) throw(ZlibError);
 	~GzipOutputStream();
 
 	/**
-	 * Check whether the constructor has succeeded.
-	 */
-	bool IsDefined() const {
-		return z.opaque == nullptr;
-	}
-
-	/**
 	 * Finish the file and write all data remaining in zlib's
 	 * output buffer.
 	 */

src/lib/zlib/Error.cxx

+/*
+ * Copyright (C) 2003-2015 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "Error.hxx"
+
+#include <zlib.h>
+
+const char *
+ZlibError::what() const noexcept
+{
+	return zError(code);
+}

src/lib/zlib/Error.hxx

+/*
+ * Copyright (C) 2003-2015 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_ZLIB_ERROR_HXX
+#define MPD_ZLIB_ERROR_HXX
+
+#include <stdexcept>
+
+class ZlibError final : public std::exception {
+	int code;
+
+public:
+	explicit ZlibError(int _code):code(_code) {}
+
+	int GetCode() const {
+		return code;
+	}
+
+	const char *what() const noexcept override;
+};
+
+#endif

test/run_gzip.cxx

@@ -20,6 +20,7 @@
 #include "config.h"
 #include "fs/io/GzipOutputStream.hxx"
 #include "fs/io/StdioOutputStream.hxx"
+#include "Log.hxx"
 #include "util/Error.hxx"
 
 #include <stdio.h>
@@ -48,9 +49,8 @@ Copy(OutputStream &dest, int src, Error &error)
 static bool
 CopyGzip(OutputStream &_dest, int src, Error &error)
 {
-	GzipOutputStream dest(_dest, error);
-	return dest.IsDefined() &&
-		Copy(dest, src, error) &&
+	GzipOutputStream dest(_dest);
+	return Copy(dest, src, error) &&
 		dest.Flush(error);
 }
 
@@ -69,11 +69,16 @@ main(int argc, gcc_unused char **argv)
 		return EXIT_FAILURE;
 	}
 
-	Error error;
-	if (!CopyGzip(stdout, STDIN_FILENO, error)) {
-		fprintf(stderr, "%s\n", error.GetMessage());
+	try {
+		Error error;
+		if (!CopyGzip(stdout, STDIN_FILENO, error)) {
+			fprintf(stderr, "%s\n", error.GetMessage());
+			return EXIT_FAILURE;
+		}
+
+		return EXIT_SUCCESS;
+	} catch (const std::exception &e) {
+		LogError(e);
 		return EXIT_FAILURE;
 	}
-
-	return EXIT_SUCCESS;
 }