fs/Charset: move code to wrapper class IcuConverter

Prepare for a ICU-based backend without GLib.

4 files changed, 183 insertions, 65 deletions

diff --git a/Makefile.am b/Makefile.am
index f4138116a..3e8e4897a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -57,9 +57,9 @@ src_mpd_LDADD = \
 	libevent.a \
 	libthread.a \
 	libsystem.a \
-	$(ICU_LDADD) \
 	libutil.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	$(SYSTEMD_DAEMON_LIBS) \
 	$(GLIB_LIBS)
 
@@ -452,6 +452,7 @@ libevent_a_SOURCES = \
 
 libicu_a_SOURCES = \
 	src/lib/icu/Collate.cxx src/lib/icu/Collate.hxx \
+	src/lib/icu/Converter.cxx src/lib/icu/Converter.hxx \
 	src/lib/icu/Error.cxx src/lib/icu/Error.hxx
 
 if HAVE_ICU
@@ -1542,6 +1543,7 @@ endif
 test_read_conf_LDADD = \
 	libconf.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	libutil.a \
 	$(GLIB_LIBS)
@@ -1589,6 +1591,7 @@ endif
 test_run_storage_LDADD = \
 	$(STORAGE_LIBS) \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libevent.a \
 	libthread.a \
 	libsystem.a \
@@ -1611,6 +1614,7 @@ test_run_input_LDADD = \
 	libevent.a \
 	libthread.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	$(GLIB_LIBS)
 test_run_input_SOURCES = test/run_input.cxx \
@@ -1635,6 +1639,7 @@ test_run_neighbor_explorer_LDADD = $(AM_LDADD) \
 	libconf.a \
 	libevent.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	libthread.a \
 	libutil.a
@@ -1662,6 +1667,7 @@ test_visit_archive_LDADD = \
 	libevent.a \
 	libthread.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	$(GLIB_LIBS)
 test_visit_archive_SOURCES = test/visit_archive.cxx \
@@ -1687,6 +1693,7 @@ test_run_gunzip_LDADD = \
 	$(GLIB_LIBS) \
 	libutil.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a
 
 endif
@@ -1698,6 +1705,7 @@ test_dump_text_file_LDADD = \
 	libconf.a \
 	libevent.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	libthread.a \
 	libutil.a \
@@ -1719,6 +1727,7 @@ test_dump_playlist_LDADD = \
 	libevent.a \
 	libthread.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	libutil.a \
 	libpcm.a \
@@ -1750,6 +1759,7 @@ test_run_decoder_LDADD = \
 	libevent.a \
 	libthread.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	libutil.a \
 	$(GLIB_LIBS)
@@ -1776,6 +1786,7 @@ test_read_tags_LDADD = \
 	libevent.a \
 	libthread.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	libutil.a \
 	$(GLIB_LIBS)
@@ -1802,6 +1813,7 @@ test_run_filter_LDADD = \
 	$(FILTER_LIBS) \
 	libconf.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	libutil.a \
 	$(GLIB_LIBS)
@@ -1830,6 +1842,7 @@ test_run_encoder_LDADD = \
 	libpcm.a \
 	libthread.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	libutil.a \
 	$(GLIB_LIBS)
@@ -1852,6 +1865,7 @@ test_test_vorbis_encoder_LDADD = $(MPD_LIBS) \
 	$(TAG_LIBS) \
 	libconf.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	libutil.a \
 	$(GLIB_LIBS)
@@ -1911,6 +1925,7 @@ test_run_output_LDADD = $(MPD_LIBS) \
 	libconf.a \
 	libevent.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	libthread.a \
 	libutil.a \
@@ -1940,6 +1955,7 @@ test_read_mixer_LDADD = \
 	libconf.a \
 	libevent.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	libutil.a \
 	$(GLIB_LIBS)
@@ -2075,6 +2091,7 @@ test_test_translate_song_LDADD = \
 	$(STORAGE_LIBS) \
 	libtag.a \
 	$(FS_LIBS) \
+	$(ICU_LDADD) \
 	libsystem.a \
 	libutil.a \
 	$(GLIB_LIBS) \
diff --git a/src/fs/Charset.cxx b/src/fs/Charset.cxx
index fb7313a35..453962c1f 100644
--- a/src/fs/Charset.cxx
+++ b/src/fs/Charset.cxx
@@ -23,12 +23,8 @@
 #include "Limits.hxx"
 #include "Log.hxx"
 #include "Traits.hxx"
+#include "lib/icu/Converter.hxx"
 #include "util/Error.hxx"
-#include "util/Domain.hxx"
-
-#ifdef HAVE_GLIB
-#include <glib.h>
-#endif
 
 #include <algorithm>
 
@@ -37,49 +33,19 @@
 
 #ifdef HAVE_FS_CHARSET
 
-static constexpr Domain convert_domain("convert");
-
-/**
- * Maximal number of bytes required to represent path name in UTF-8
- * (including nul-terminator).
- * This value is a rought estimate of upper bound.
- * It's based on path name limit in bytes (MPD_PATH_MAX)
- * and assumption that some weird encoding could represent some UTF-8 4 byte
- * sequences with single byte.
- */
-static constexpr size_t MPD_PATH_MAX_UTF8 = (MPD_PATH_MAX - 1) * 4 + 1;
-
 static std::string fs_charset;
 
-gcc_pure
-static bool
-CheckCharset(const char *charset, Error &error)
-{
-	/* convert a space to check if the charset is valid */
-	GError *error2 = nullptr;
-	char *test = g_convert(" ", 1, charset, "UTF-8", nullptr, nullptr, &error2);
-	if (test == nullptr) {
-		error.Set(convert_domain, error2->code, error2->message);
-		g_error_free(error2);
-		return false;
-	}
-
-	g_free(test);
-	return true;
-}
+static IcuConverter *fs_converter;
 
 bool
 SetFSCharset(const char *charset, Error &error)
 {
 	assert(charset != nullptr);
+	assert(fs_converter == nullptr);
 
-	if (!CheckCharset(charset, error)) {
-		error.FormatPrefix("Failed to initialize filesystem charset '%s': ",
-				   charset);
+	fs_converter = IcuConverter::Create(charset, error);
+	if (fs_converter == nullptr)
 		return false;
-	}
-
-	fs_charset = charset;
 
 	FormatDebug(path_domain,
 		    "SetFSCharset: fs charset is: %s", fs_charset.c_str());
@@ -91,6 +57,10 @@ SetFSCharset(const char *charset, Error &error)
 void
 DeinitFSCharset()
 {
+#ifdef HAVE_ICU_CONVERTER
+	delete fs_converter;
+	fs_converter = nullptr;
+#endif
 }
 
 const char *
@@ -122,7 +92,7 @@ PathToUTF8(const char *path_fs)
 	assert(path_fs != nullptr);
 
 #ifdef HAVE_FS_CHARSET
-	if (fs_charset.empty()) {
+	if (fs_converter == nullptr) {
 #endif
 		auto result = std::string(path_fs);
 		FixSeparators(result);
@@ -130,26 +100,7 @@ PathToUTF8(const char *path_fs)
 #ifdef HAVE_FS_CHARSET
 	}
 
-	GIConv conv = g_iconv_open("utf-8", fs_charset.c_str());
-	if (conv == reinterpret_cast<GIConv>(-1))
-		return std::string();
-
-	// g_iconv() does not need nul-terminator,
-	// std::string could be created without it too.
-	char path_utf8[MPD_PATH_MAX_UTF8 - 1];
-	char *in = const_cast<char *>(path_fs);
-	char *out = path_utf8;
-	size_t in_left = strlen(path_fs);
-	size_t out_left = sizeof(path_utf8);
-
-	size_t ret = g_iconv(conv, &in, &in_left, &out, &out_left);
-
-	g_iconv_close(conv);
-
-	if (ret == static_cast<size_t>(-1) || in_left > 0)
-		return std::string();
-
-	auto result_path = std::string(path_utf8, sizeof(path_utf8) - out_left);
+	auto result_path = fs_converter->ToUTF8(path_fs);
 	FixSeparators(result_path);
 	return result_path;
 #endif
@@ -162,12 +113,10 @@ PathFromUTF8(const char *path_utf8)
 {
 	assert(path_utf8 != nullptr);
 
-	if (fs_charset.empty())
+	if (fs_converter == nullptr)
 		return path_utf8;
 
-	return g_convert(path_utf8, -1,
-			 fs_charset.c_str(), "utf-8",
-			 nullptr, nullptr, nullptr);
+	return fs_converter->FromUTF8(path_utf8);
 }
 
 #endif
diff --git a/src/lib/icu/Converter.cxx b/src/lib/icu/Converter.cxx
new file mode 100644
index 000000000..7378f8636
--- /dev/null
+++ b/src/lib/icu/Converter.cxx
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2003-2014 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 "Converter.hxx"
+#include "util/Error.hxx"
+#include "util/Domain.hxx"
+
+#include <string.h>
+
+#ifdef HAVE_GLIB
+static constexpr Domain g_iconv_domain("g_iconv");
+#endif
+
+#ifdef HAVE_ICU_CONVERTER
+
+IcuConverter *
+IcuConverter::Create(const char *charset, Error &error)
+{
+	GIConv to = g_iconv_open("utf-8", charset);
+	GIConv from = g_iconv_open(charset, "utf-8");
+	if (to == (GIConv)-1 || from == (GIConv)-1) {
+		if (to != (GIConv)-1)
+			g_iconv_close(to);
+		if (from != (GIConv)-1)
+			g_iconv_close(from);
+		error.Format(g_iconv_domain,
+			     "Failed to initialize charset '%s'", charset);
+		return nullptr;
+	}
+
+	return new IcuConverter(to, from);
+}
+
+static std::string
+DoConvert(GIConv conv, const char *src)
+{
+	char buffer[4096];
+	char *in = const_cast<char *>(src);
+	char *out = buffer;
+	size_t in_left = strlen(src);
+	size_t out_left = sizeof(buffer);
+
+	size_t n = g_iconv(conv, &in, &in_left, &out, &out_left);
+
+	if (n == static_cast<size_t>(-1) || in_left > 0)
+		return std::string();
+
+	return std::string(buffer, sizeof(buffer) - out_left);
+}
+
+std::string
+IcuConverter::ToUTF8(const char *s) const
+{
+	return DoConvert(to_utf8, s);
+}
+
+std::string
+IcuConverter::FromUTF8(const char *s) const
+{
+	return DoConvert(from_utf8, s);
+}
+
+#endif
diff --git a/src/lib/icu/Converter.hxx b/src/lib/icu/Converter.hxx
new file mode 100644
index 000000000..f20dc6f7c
--- /dev/null
+++ b/src/lib/icu/Converter.hxx
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2003-2014 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_ICU_CONVERTER_HXX
+#define MPD_ICU_CONVERTER_HXX
+
+#include "check.h"
+#include "Compiler.h"
+
+#ifdef HAVE_GLIB
+#include <glib.h>
+#define HAVE_ICU_CONVERTER
+#endif
+
+#ifdef HAVE_ICU_CONVERTER
+
+#include <string>
+
+class Error;
+
+/**
+ * This class can convert strings with a certain character set to and
+ * from UTF-8.
+ */
+class IcuConverter {
+	const GIConv to_utf8, from_utf8;
+
+	IcuConverter(GIConv _to, GIConv _from)
+		:to_utf8(_to), from_utf8(_from) {}
+
+public:
+	~IcuConverter() {
+		g_iconv_close(to_utf8);
+		g_iconv_close(from_utf8);
+	}
+
+	static IcuConverter *Create(const char *charset, Error &error);
+
+	/**
+	 * Convert the string to UTF-8.
+	 * Returns empty string on error.
+	 */
+	gcc_pure gcc_nonnull_all
+	std::string ToUTF8(const char *s) const;
+
+	/**
+	 * Convert the string from UTF-8.
+	 * Returns empty string on error.
+	 */
+	gcc_pure gcc_nonnull_all
+	std::string FromUTF8(const char *s) const;
+};
+
+#endif
+
+#endif