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

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
@@ -43,20 +43,11 @@ 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.