util/Error: new error passing library

Replaces GLib's GError.

src/util/Domain.hxx

@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2003-2013 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_DOMAIN_HXX
+#define MPD_DOMAIN_HXX
+
+class Domain {
+	const char *const name;
+
+public:
+	constexpr explicit Domain(const char *_name)
+		:name(_name) {}
+
+	Domain(const Domain &) = delete;
+	Domain &operator=(const Domain &) = delete;
+
+	constexpr const char *GetName() const {
+		return name;
+	}
+
+	bool operator==(const Domain &other) const {
+		return this == &other;
+	}
+
+	bool operator!=(const Domain &other) const {
+		return !(*this == other);
+	}
+};
+
+#endif

src/util/Error.cxx

@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2003-2013 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 "Domain.hxx"
+
+#include <glib.h>
+
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+
+const Domain errno_domain("errno");
+
+Error::~Error() {}
+
+void
+Error::Set(const Domain &_domain, int _code, const char *_message)
+{
+	domain = &_domain;
+	code = _code;
+	message.assign(_message);
+}
+
+void
+Error::Format2(const Domain &_domain, int _code, const char *fmt, ...)
+{
+	char buffer[1024];
+	va_list ap;
+	va_start(ap, fmt);
+	vsnprintf(buffer, sizeof(buffer), fmt, ap);
+	va_end(ap);
+
+	Set(_domain, _code, buffer);
+}
+
+void
+Error::FormatPrefix(const char *fmt, ...)
+{
+	char buffer[1024];
+	va_list ap;
+	va_start(ap, fmt);
+	vsnprintf(buffer, sizeof(buffer), fmt, ap);
+	va_end(ap);
+
+	AddPrefix(buffer);
+}
+
+void
+Error::SetErrno(int e)
+{
+	Set(errno_domain, e, g_strerror(e));
+}
+
+void
+Error::SetErrno()
+{
+	SetErrno(errno);
+}
+
+void
+Error::SetErrno(int e, const char *prefix)
+{
+	Format(errno_domain, e, "%s: %s", prefix, g_strerror(e));
+}
+
+void
+Error::SetErrno(const char *prefix)
+{
+	SetErrno(errno, prefix);
+}
+
+void
+Error::FormatErrno(int e, const char *fmt, ...)
+{
+	char buffer[1024];
+	va_list ap;
+	va_start(ap, fmt);
+	vsnprintf(buffer, sizeof(buffer), fmt, ap);
+	va_end(ap);
+
+	SetErrno(e, buffer);
+}
+
+void
+Error::FormatErrno(const char *fmt, ...)
+{
+	const int e = errno;
+
+	char buffer[1024];
+	va_list ap;
+	va_start(ap, fmt);
+	vsnprintf(buffer, sizeof(buffer), fmt, ap);
+	va_end(ap);
+
+	SetErrno(e, buffer);
+}

src/util/Error.hxx

@@ -0,0 +1,162 @@
+/*
+ * Copyright (C) 2003-2013 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_ERROR_HXX
+#define MPD_ERROR_HXX
+
+#include "check.h"
+#include "gcc.h"
+
+#include <string>
+
+#include <assert.h>
+
+class Domain;
+
+extern const Domain errno_domain;
+
+#ifdef WIN32
+/* fuck WIN32! */
+#include <windows.h>
+#define IgnoreError MPDIgnoreError
+#undef GetMessage
+#endif
+
+/**
+ * This class contains information about a runtime error.
+ */
+class Error {
+	const Domain *domain;
+	int code;
+	std::string message;
+
+public:
+	Error():domain(nullptr), code(0) {}
+
+	Error(const Domain &_domain, int _code, const char *_message)
+		:domain(&_domain), code(_code), message(_message) {}
+
+	Error(const Domain &_domain, const char *_message)
+		:domain(&_domain), code(0), message(_message) {}
+
+	Error(Error &&other)
+		:domain(other.domain), code(other.code),
+		 message(std::move(other.message)) {}
+
+	~Error();
+
+	Error(const Error &) = delete;
+	Error &operator=(const Error &) = delete;
+
+	Error &operator=(Error &&other) {
+		domain = other.domain;
+		code = other.code;
+		std::swap(message, other.message);
+		return *this;
+	}
+
+	bool IsDefined() const {
+		return domain != nullptr;
+	}
+
+	void Clear() {
+		domain = nullptr;
+	}
+
+	const Domain &GetDomain() const {
+		assert(IsDefined());
+
+		return *domain;
+	}
+
+	bool IsDomain(const Domain &other) const {
+		return domain == &other;
+	}
+
+	int GetCode() const {
+		assert(IsDefined());
+
+		return code;
+	}
+
+	const char *GetMessage() const {
+		assert(IsDefined());
+
+		return message.c_str();
+	}
+
+	void Set(const Error &other) {
+		assert(!IsDefined());
+		assert(other.IsDefined());
+
+		domain = other.domain;
+		code = other.code;
+		message = other.message;
+	}
+
+	void Set(const Domain &_domain, int _code, const char *_message);
+
+	void Set(const Domain &_domain, const char *_message) {
+		Set(_domain, 0, _message);
+	}
+
+private:
+	void Format2(const Domain &_domain, int _code, const char *fmt, ...);
+
+public:
+	template<typename... Args>
+	void Format(const Domain &_domain, int _code,
+		    const char *fmt, Args&&... args) {
+		Format2(_domain, _code, fmt, std::forward<Args>(args)...);
+	}
+
+	template<typename... Args>
+	void Format(const Domain &_domain, const char *fmt, Args&&... args) {
+		Format2(_domain, 0, fmt, std::forward<Args>(args)...);
+	}
+
+	void AddPrefix(const char *prefix) {
+		message.insert(0, prefix);
+	}
+
+	void FormatPrefix(const char *fmt, ...);
+
+	void SetErrno(int e);
+	void SetErrno();
+	void SetErrno(int e, const char *prefix);
+	void SetErrno(const char *prefix);
+	void FormatErrno(const char *prefix, ...);
+	void FormatErrno(int e, const char *prefix, ...);
+};
+
+/**
+ * Pass a temporary instance of this class to ignore errors.
+ */
+class IgnoreError final {
+	Error error;
+
+public:
+	operator Error &() {
+		assert(!error.IsDefined());
+
+		return error;
+	}
+};
+
+#endif

src/util/Tokenizer.cxx

@@ -20,18 +20,15 @@
 #include "config.h"
 #include "Tokenizer.hxx"
 #include "StringUtil.hxx"
+#include "Error.hxx"
+#include "Domain.hxx"
 
 #include <glib.h>
 
 #include <assert.h>
 #include <string.h>
 
-gcc_const
-static GQuark
-tokenizer_quark(void)
-{
-	return g_quark_from_static_string("tokenizer");
-}
+static constexpr Domain tokenizer_domain("tokenizer");
 
 static inline bool
 valid_word_first_char(char ch)
@@ -46,7 +43,7 @@ valid_word_char(char ch)
 }
 
 char *
-Tokenizer::NextWord(GError **error_r)
+Tokenizer::NextWord(Error &error)
 {
 	char *const word = input;
 
@@ -56,8 +53,7 @@ Tokenizer::NextWord(GError **error_r)
 	/* check the first character */
 
 	if (!valid_word_first_char(*input)) {
-		g_set_error(error_r, tokenizer_quark(), 0,
-			    "Letter expected");
+		error.Set(tokenizer_domain, "Letter expected");
 		return nullptr;
 	}
 
@@ -74,8 +70,7 @@ Tokenizer::NextWord(GError **error_r)
 		}
 
 		if (!valid_word_char(*input)) {
-			g_set_error(error_r, tokenizer_quark(), 0,
-				    "Invalid word character");
+			error.Set(tokenizer_domain, "Invalid word character");
 			return nullptr;
 		}
 	}
@@ -93,7 +88,7 @@ valid_unquoted_char(char ch)
 }
 
 char *
-Tokenizer::NextUnquoted(GError **error_r)
+Tokenizer::NextUnquoted(Error &error)
 {
 	char *const word = input;
 
@@ -103,8 +98,7 @@ Tokenizer::NextUnquoted(GError **error_r)
 	/* check the first character */
 
 	if (!valid_unquoted_char(*input)) {
-		g_set_error(error_r, tokenizer_quark(), 0,
-			    "Invalid unquoted character");
+		error.Set(tokenizer_domain, "Invalid unquoted character");
 		return nullptr;
 	}
 
@@ -121,8 +115,8 @@ Tokenizer::NextUnquoted(GError **error_r)
 		}
 
 		if (!valid_unquoted_char(*input)) {
-			g_set_error(error_r, tokenizer_quark(), 0,
-				    "Invalid unquoted character");
+			error.Set(tokenizer_domain,
+				  "Invalid unquoted character");
 			return nullptr;
 		}
 	}
@@ -134,7 +128,7 @@ Tokenizer::NextUnquoted(GError **error_r)
 }
 
 char *
-Tokenizer::NextString(GError **error_r)
+Tokenizer::NextString(Error &error)
 {
 	char *const word = input, *dest = input;
 
@@ -145,8 +139,7 @@ Tokenizer::NextString(GError **error_r)
 	/* check for the opening " */
 
 	if (*input != '"') {
-		g_set_error(error_r, tokenizer_quark(), 0,
-			    "'\"' expected");
+		error.Set(tokenizer_domain, "'\"' expected");
 		return nullptr;
 	}
 
@@ -165,8 +158,7 @@ Tokenizer::NextString(GError **error_r)
 			   difference between "end of line" and
 			   "error" */
 			--input;
-			g_set_error(error_r, tokenizer_quark(), 0,
-				    "Missing closing '\"'");
+			error.Set(tokenizer_domain, "Missing closing '\"'");
 			return nullptr;
 		}
 
@@ -179,8 +171,8 @@ Tokenizer::NextString(GError **error_r)
 
 	++input;
 	if (*input != 0 && !g_ascii_isspace(*input)) {
-		g_set_error(error_r, tokenizer_quark(), 0,
-			    "Space expected after closing '\"'");
+		error.Set(tokenizer_domain,
+			  "Space expected after closing '\"'");
 		return nullptr;
 	}
 
@@ -192,10 +184,10 @@ Tokenizer::NextString(GError **error_r)
 }
 
 char *
-Tokenizer::NextParam(GError **error_r)
+Tokenizer::NextParam(Error &error)
 {
 	if (*input == '"')
-		return NextString(error_r);
+		return NextString(error);
 	else
-		return NextUnquoted(error_r);
+		return NextUnquoted(error);
 }

src/util/Tokenizer.hxx

@@ -20,7 +20,7 @@
 #ifndef MPD_TOKENIZER_HXX
 #define MPD_TOKENIZER_HXX
 
-#include "gerror.h"
+class Error;
 
 class Tokenizer {
 	char *input;
@@ -50,23 +50,23 @@ public:
 	/**
 	 * Reads the next word.
 	 *
-	 * @param error_r if this function returns nullptr and
-	 * **input_p!=0, it optionally provides a GError object in
+	 * @param error if this function returns nullptr and
+	 * **input_p!=0, it provides an #Error object in
 	 * this argument
 	 * @return a pointer to the null-terminated word, or nullptr
 	 * on error or end of line
 	 */
-	char *NextWord(GError **error_r);
+	char *NextWord(Error &error);
 
 	/**
 	 * Reads the next unquoted word from the input string.
 	 *
 	 * @param error_r if this function returns nullptr and **input_p!=0, it
-	 * optionally provides a GError object in this argument
+	 * provides an #Error object in this argument
 	 * @return a pointer to the null-terminated word, or nullptr
 	 * on error or end of line
 	 */
-	char *NextUnquoted(GError **error_r);
+	char *NextUnquoted(Error &error);
 
 	/**
 	 * Reads the next quoted string from the input string.  A backslash
@@ -76,11 +76,11 @@ public:
 	 * @param input_p the input string; this function returns a pointer to
 	 * the first non-whitespace character of the following token
 	 * @param error_r if this function returns nullptr and **input_p!=0, it
-	 * optionally provides a GError object in this argument
+	 * provides an #Error object in this argument
 	 * @return a pointer to the null-terminated string, or nullptr on error
 	 * or end of line
 	 */
-	char *NextString(GError **error_r);
+	char *NextString(Error &error);
 
 	/**
 	 * Reads the next unquoted word or quoted string from the
@@ -88,12 +88,12 @@ public:
 	 * NextString().
 	 *
 	 * @param error_r if this function returns nullptr and
-	 * **input_p!=0, it optionally provides a GError object in
+	 * **input_p!=0, it provides an #Error object in
 	 * this argument
 	 * @return a pointer to the null-terminated string, or nullptr
 	 * on error or end of line
 	 */
-	char *NextParam(GError **error_r);
+	char *NextParam(Error &error);
 };
 
 #endif