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author | Max Kellermann <max@duempel.org> | 2014-08-07 18:54:06 +0200 |
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committer | Max Kellermann <max@duempel.org> | 2014-08-07 19:38:25 +0200 |
commit | aa2e4d92e0005f4516eb591803120eff89f99109 (patch) | |
tree | beb83ec24f0cb5b527ec60bd56c2722681f1d3f5 /src/fs/io | |
parent | 0ea66a1275da319e2443fa1536cec7ea7fc53b53 (diff) | |
download | mpd-aa2e4d92e0005f4516eb591803120eff89f99109.tar.gz mpd-aa2e4d92e0005f4516eb591803120eff89f99109.tar.xz mpd-aa2e4d92e0005f4516eb591803120eff89f99109.zip |
fs/io/BufferedReader: new class to replace class TextFile
The new class is pluggable, to prepare for gzipped database files.
For now, the TextFile class remains, and will be refactored away
later.
Diffstat (limited to 'src/fs/io')
-rw-r--r-- | src/fs/io/BufferedReader.cxx | 82 | ||||
-rw-r--r-- | src/fs/io/BufferedReader.hxx | 75 | ||||
-rw-r--r-- | src/fs/io/TextFile.cxx | 59 | ||||
-rw-r--r-- | src/fs/io/TextFile.hxx | 18 |
4 files changed, 177 insertions, 57 deletions
diff --git a/src/fs/io/BufferedReader.cxx b/src/fs/io/BufferedReader.cxx new file mode 100644 index 000000000..ba2f17dcf --- /dev/null +++ b/src/fs/io/BufferedReader.cxx @@ -0,0 +1,82 @@ +/* + * 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 "BufferedReader.hxx" +#include "Reader.hxx" +#include "util/TextFile.hxx" + +bool +BufferedReader::Fill(bool need_more) +{ + if (gcc_unlikely(last_error.IsDefined())) + return false; + + if (eof) + return !need_more; + + auto w = buffer.Write(); + if (w.IsEmpty()) { + if (buffer.GetCapacity() >= MAX_SIZE) + return !need_more; + + buffer.Grow(buffer.GetCapacity() * 2); + w = buffer.Write(); + assert(!w.IsEmpty()); + } + + size_t nbytes = reader.Read(w.data, w.size, last_error); + if (nbytes == 0) { + if (gcc_unlikely(last_error.IsDefined())) + return false; + + eof = true; + return !need_more; + } + + buffer.Append(nbytes); + return true; +} + +char * +BufferedReader::ReadLine() +{ + do { + char *line = ReadBufferedLine(buffer); + if (line != nullptr) + return line; + } while (Fill(true)); + + if (last_error.IsDefined() || !eof || buffer.IsEmpty()) + return nullptr; + + auto w = buffer.Write(); + if (w.IsEmpty()) { + buffer.Grow(buffer.GetCapacity() + 1); + w = buffer.Write(); + assert(!w.IsEmpty()); + } + + /* terminate the last line */ + w[0] = 0; + + char *line = buffer.Read().data; + buffer.Clear(); + return line; +} diff --git a/src/fs/io/BufferedReader.hxx b/src/fs/io/BufferedReader.hxx new file mode 100644 index 000000000..61cc8df83 --- /dev/null +++ b/src/fs/io/BufferedReader.hxx @@ -0,0 +1,75 @@ +/* + * 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_BUFFERED_READER_HXX +#define MPD_BUFFERED_READER_HXX + +#include "check.h" +#include "Compiler.h" +#include "util/DynamicFifoBuffer.hxx" +#include "util/Error.hxx" + +#include <stddef.h> + +class Reader; +class Error; + +class BufferedReader { + static constexpr size_t MAX_SIZE = 512 * 1024; + + Reader &reader; + + DynamicFifoBuffer<char> buffer; + + Error last_error; + + bool eof; + +public: + BufferedReader(Reader &_reader) + :reader(_reader), buffer(4096), eof(false) {} + + gcc_pure + bool Check() const { + return !last_error.IsDefined(); + } + + bool Check(Error &error) const { + if (last_error.IsDefined()) { + error.Set(last_error); + return false; + } else + return true; + } + + bool Fill(bool need_more); + + gcc_pure + WritableBuffer<void> Read() const { + return buffer.Read().ToVoid(); + } + + void Consume(size_t n) { + buffer.Consume(n); + } + + char *ReadLine(); +}; + +#endif diff --git a/src/fs/io/TextFile.cxx b/src/fs/io/TextFile.cxx index b1a92b9cc..396d0f9cd 100644 --- a/src/fs/io/TextFile.cxx +++ b/src/fs/io/TextFile.cxx @@ -19,63 +19,30 @@ #include "config.h" #include "TextFile.hxx" -#include "util/Alloc.hxx" +#include "FileReader.hxx" +#include "BufferedReader.hxx" #include "fs/Path.hxx" -#include "fs/FileSystem.hxx" #include <assert.h> -#include <string.h> -#include <stdlib.h> -TextFile::TextFile(Path path_fs) - :file(FOpen(path_fs, FOpenMode::ReadText)), - buffer((char *)xalloc(step)), capacity(step), length(0) {} +TextFile::TextFile(Path path_fs, Error &error) + :file_reader(new FileReader(path_fs, error)), + buffered_reader(file_reader->IsDefined() + ? new BufferedReader(*file_reader) + : nullptr) +{ +} TextFile::~TextFile() { - free(buffer); - - if (file != nullptr) - fclose(file); + delete buffered_reader; + delete file_reader; } char * TextFile::ReadLine() { - assert(file != nullptr); - - while (true) { - if (length >= capacity) { - if (capacity >= max_length) - /* too large already - bail out */ - return nullptr; - - capacity <<= 1; - char *new_buffer = (char *)realloc(buffer, capacity); - if (new_buffer == nullptr) - /* out of memory - bail out */ - return nullptr; - } - - char *p = fgets(buffer + length, capacity - length, file); - if (p == nullptr) { - if (length == 0 || ferror(file)) - return nullptr; - break; - } - - length += strlen(buffer + length); - if (buffer[length - 1] == '\n') - break; - } - - /* remove the newline characters */ - if (buffer[length - 1] == '\n') - --length; - if (buffer[length - 1] == '\r') - --length; + assert(buffered_reader != nullptr); - buffer[length] = 0; - length = 0; - return buffer; + return buffered_reader->ReadLine(); } diff --git a/src/fs/io/TextFile.hxx b/src/fs/io/TextFile.hxx index e3a712a88..33a1b8060 100644 --- a/src/fs/io/TextFile.hxx +++ b/src/fs/io/TextFile.hxx @@ -22,29 +22,26 @@ #include "Compiler.h" -#include <stdio.h> #include <stddef.h> class Path; +class Error; +class FileReader; +class BufferedReader; class TextFile { - static constexpr size_t max_length = 512 * 1024; - static constexpr size_t step = 1024; - - FILE *const file; - - char *buffer; - size_t capacity, length; + FileReader *const file_reader; + BufferedReader *const buffered_reader; public: - TextFile(Path path_fs); + TextFile(Path path_fs, Error &error); TextFile(const TextFile &other) = delete; ~TextFile(); bool HasFailed() const { - return gcc_unlikely(file == nullptr); + return gcc_unlikely(buffered_reader == nullptr); } /** @@ -53,7 +50,6 @@ public: * 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(); |