TextFile: move to fs subsystem

src/fs/TextFile.cxx

@@ -0,0 +1,77 @@
+/*
+ * 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 "TextFile.hxx"
+#include "fs/Path.hxx"
+#include "fs/FileSystem.hxx"
+
+#include <glib.h>
+
+#include <assert.h>
+#include <string.h>
+
+TextFile::TextFile(Path path_fs)
+	:file(FOpen(path_fs, FOpenMode::ReadText)),
+	 buffer(g_string_sized_new(step)) {}
+
+TextFile::~TextFile()
+{
+	if (file != nullptr)
+		fclose(file);
+
+	g_string_free(buffer, true);
+}
+
+char *
+TextFile::ReadLine()
+{
+	gsize length = 0, i;
+	char *p;
+
+	assert(file != nullptr);
+	assert(buffer != nullptr);
+	assert(buffer->allocated_len >= step);
+
+	while (buffer->len < max_length) {
+		p = fgets(buffer->str + length,
+			  buffer->allocated_len - length, file);
+		if (p == nullptr) {
+			if (length == 0 || ferror(file))
+				return nullptr;
+			break;
+		}
+
+		i = strlen(buffer->str + length);
+		length += i;
+		if (i < step - 1 || buffer->str[length - 1] == '\n')
+			break;
+
+		g_string_set_size(buffer, length + step);
+	}
+
+	/* remove the newline characters */
+	if (buffer->str[length - 1] == '\n')
+		--length;
+	if (buffer->str[length - 1] == '\r')
+		--length;
+
+	g_string_set_size(buffer, length);
+	return buffer->str;
+}

src/fs/TextFile.hxx

@@ -0,0 +1,61 @@
+/*
+ * 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_TEXT_FILE_HXX
+#define MPD_TEXT_FILE_HXX
+
+#include "Compiler.h"
+
+#include <stdio.h>
+
+class Path;
+typedef struct _GString GString;
+
+class TextFile {
+	static constexpr size_t max_length = 512 * 1024;
+	static constexpr size_t step = 1024;
+
+	FILE *const file;
+
+	GString *const buffer;
+
+public:
+	TextFile(Path path_fs);
+
+	TextFile(const TextFile &other) = delete;
+
+	~TextFile();
+
+	bool HasFailed() const {
+		return gcc_unlikely(file == nullptr);
+	}
+
+	/**
+	 * Reads a line from the input file, and strips trailing
+	 * space.  There is a reasonable maximum line length, only to
+	 * prevent denial of service.
+	 *
+	 * @param file the source file, opened in text mode
+	 * @param buffer an allocator for the buffer
+	 * @return a pointer to the line, or nullptr on end-of-file or error
+	 */
+	char *ReadLine();
+};
+
+#endif