From 5277297336eb2d9db0ba9f86e6a5f638f04b06af Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@musicpd.org>
Date: Thu, 9 May 2019 11:39:30 +0200
Subject: [PATCH] input/buffered: move basic buffering code to class
BufferingInputStream
Prepare to reuse it in another class.
---
src/input/BufferedInputStream.cxx | 193 +++-----------------------
src/input/BufferedInputStream.hxx | 52 +------
src/input/BufferingInputStream.cxx | 213 +++++++++++++++++++++++++++++
src/input/BufferingInputStream.hxx | 100 ++++++++++++++
src/input/meson.build | 1 +
5 files changed, 337 insertions(+), 222 deletions(-)
create mode 100644 src/input/BufferingInputStream.cxx
create mode 100644 src/input/BufferingInputStream.hxx
diff --git a/src/input/BufferedInputStream.cxx b/src/input/BufferedInputStream.cxx
index 29c6ebd1b..55eb07b5d 100644
--- a/src/input/BufferedInputStream.cxx
+++ b/src/input/BufferedInputStream.cxx
@@ -1,5 +1,5 @@
/*
- * Copyright 2003-2018 The Music Player Daemon Project
+ * Copyright 2003-2019 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
@@ -25,212 +25,51 @@
BufferedInputStream::BufferedInputStream(InputStreamPtr _input)
:InputStream(_input->GetURI(), _input->mutex),
- input(std::move(_input)),
- thread(BIND_THIS_METHOD(RunThread)),
- buffer(input->GetSize())
+ BufferingInputStream(std::move(_input))
{
- assert(IsEligible(*input));
+ assert(IsEligible(GetInput()));
- input->SetHandler(this);
+ if (GetInput().HasMimeType())
+ SetMimeType(GetInput().GetMimeType());
- if (input->HasMimeType())
- SetMimeType(input->GetMimeType());
-
- size = input->GetSize();
- seekable = input->IsSeekable();
- offset = input->GetOffset();
+ InputStream::size = BufferingInputStream::size();
+ InputStream::seekable = GetInput().IsSeekable();
+ InputStream::offset = GetInput().GetOffset();
SetReady();
-
- thread.Start();
-}
-
-BufferedInputStream::~BufferedInputStream() noexcept
-{
- {
- const std::lock_guard<Mutex> lock(mutex);
- stop = true;
- wake_cond.notify_one();
- }
-
- thread.Join();
}
void
BufferedInputStream::Check()
{
- if (input)
- input->Check();
+ BufferingInputStream::Check();
}
void
BufferedInputStream::Seek(std::unique_lock<Mutex> &lock,
offset_type new_offset)
{
- if (new_offset >= size) {
- offset = size;
- return;
- }
-
- auto r = buffer.Read(new_offset);
- if (r.HasData()) {
- /* nice, we already have some data at the desired
- offset and this method call is a no-op */
- offset = new_offset;
- return;
- }
-
- seek_offset = new_offset;
- seek = true;
- wake_cond.notify_one();
-
- client_cond.wait(lock, [this]{ return !seek; });
-
- if (seek_error)
- std::rethrow_exception(std::exchange(seek_error, {}));
-
- offset = new_offset;
+ BufferingInputStream::Seek(lock, new_offset);
+ InputStream::offset = new_offset;
}
bool
BufferedInputStream::IsEOF() noexcept
{
- return offset == size;
+ return InputStream::offset == BufferingInputStream::size();
}
bool
BufferedInputStream::IsAvailable() noexcept
{
- return IsEOF() || buffer.Read(offset).HasData();
+ return BufferingInputStream::IsAvailable();
}
size_t
BufferedInputStream::Read(std::unique_lock<Mutex> &lock,
void *ptr, size_t s)
{
- if (offset >= size)
- return 0;
-
- while (true) {
- assert(size == buffer.size());
-
- auto r = buffer.Read(offset);
- if (r.HasData()) {
- /* yay, we have some data */
- size_t nbytes = std::min(s, r.defined_buffer.size);
- memcpy(ptr, r.defined_buffer.data, nbytes);
- offset += nbytes;
-
- if (!IsAvailable()) {
- /* wake up the sleeping thread */
- idle = false;
- wake_cond.notify_one();
- }
-
- return nbytes;
- }
-
- if (read_error) {
- wake_cond.notify_one();
- std::rethrow_exception(std::exchange(read_error, {}));
- }
-
- if (idle) {
- /* wake up the sleeping thread */
- idle = false;
- wake_cond.notify_one();
- }
-
- client_cond.wait(lock);
- }
-}
-
-void
-BufferedInputStream::RunThread() noexcept
-{
- SetThreadName("input_buffered");
-
- std::unique_lock<Mutex> lock(mutex);
-
- while (!stop) {
- assert(size == buffer.size());
-
- if (seek) {
- try {
- input->Seek(lock, seek_offset);
- } catch (...) {
- seek_error = std::current_exception();
- }
-
- idle = false;
- seek = false;
- client_cond.notify_one();
- } else if (!idle && !read_error &&
- offset != input->GetOffset() &&
- !IsAvailable()) {
- /* a past Seek() call was a no-op because data
- was already available at that position, but
- now we've reached a new position where
- there is no more data in the buffer, and
- our input is reading somewhere else (maybe
- stuck at the end of the file); to find a
- way out, we now seek our input to our
- reading position to be able to fill our
- buffer */
-
- try {
- input->Seek(lock, offset);
- } catch (...) {
- /* this is really a seek error, but we
- register it as a read_error,
- because seek_error is only checked
- by Seek(), and at our frontend (our
- own InputStream interface) is in
- "read" mode */
- read_error = std::current_exception();
- }
- } else if (!idle && !read_error &&
- input->IsAvailable() && !input->IsEOF()) {
- const auto read_offset = input->GetOffset();
- auto w = buffer.Write(read_offset);
-
- if (w.empty()) {
- if (IsAvailable()) {
- /* we still have enough data
- for the next Read() - sleep
- until we need more data */
- idle = true;
- } else {
- /* we need more data at our
- current position, because
- the next Read() will stall
- - seek our input to our
- offset to prepare filling
- the buffer from there */
- try {
- input->Seek(lock, offset);
- } catch (...) {
- read_error = std::current_exception();
- client_cond.notify_one();
- InvokeOnAvailable();
- }
- }
-
- continue;
- }
-
- try {
- size_t nbytes = input->Read(lock,
- w.data, w.size);
- buffer.Commit(read_offset,
- read_offset + nbytes);
- } catch (...) {
- read_error = std::current_exception();
- }
-
- client_cond.notify_one();
- InvokeOnAvailable();
- } else
- wake_cond.wait(lock);
- }
+ size_t nbytes = BufferingInputStream::Read(lock, ptr, s);
+ InputStream::offset += nbytes;
+ return nbytes;
}
diff --git a/src/input/BufferedInputStream.hxx b/src/input/BufferedInputStream.hxx
index dcb6282a1..74b2ef492 100644
--- a/src/input/BufferedInputStream.hxx
+++ b/src/input/BufferedInputStream.hxx
@@ -1,5 +1,5 @@
/*
- * Copyright 2003-2018 The Music Player Daemon Project
+ * Copyright 2003-2019 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
@@ -21,13 +21,7 @@
#define MPD_BUFFERED_INPUT_STREAM_BUFFER_HXX
#include "InputStream.hxx"
-#include "Ptr.hxx"
-#include "Handler.hxx"
-#include "thread/Thread.hxx"
-#include "thread/Cond.hxx"
-#include "util/SparseBuffer.hxx"
-
-#include <exception>
+#include "BufferingInputStream.hxx"
#include <assert.h>
@@ -36,37 +30,12 @@
* #InputStream. This works only if the #InputStream is a "file", not
* a "stream"; see IsEligible() for details.
*/
-class BufferedInputStream final : public InputStream, InputStreamHandler {
- InputStreamPtr input;
-
- Thread thread;
-
- /**
- * This #Cond wakes up the #Thread. It is used by both the
- * "client" thread (to submit commands) and #input's handler
- * (to notify new data being available).
- */
- Cond wake_cond;
-
- /**
- * This #Cond wakes up the client upon command completion.
- */
- Cond client_cond;
-
- SparseBuffer<uint8_t> buffer;
-
- bool stop = false, seek = false, idle = false;
-
- offset_type seek_offset;
-
- std::exception_ptr read_error, seek_error;
-
+class BufferedInputStream final : public InputStream, BufferingInputStream {
// TODO: make configurable
static constexpr offset_type MAX_SIZE = 128 * 1024 * 1024;
public:
BufferedInputStream(InputStreamPtr _input);
- ~BufferedInputStream() noexcept override;
/**
* Check whether the given #InputStream can be used as input
@@ -93,18 +62,11 @@ public:
size_t Read(std::unique_lock<Mutex> &lock,
void *ptr, size_t size) override;
- /* virtual methods from class InputStreamHandler */
- void OnInputStreamReady() noexcept override {
- /* this should never be called, because our input must
- be "ready" already */
- }
-
- void OnInputStreamAvailable() noexcept override {
- wake_cond.notify_one();
- }
-
private:
- void RunThread() noexcept;
+ /* virtual methods from class BufferingInputStream */
+ void OnBufferAvailable() noexcept override {
+ InvokeOnAvailable();
+ }
};
#endif
diff --git a/src/input/BufferingInputStream.cxx b/src/input/BufferingInputStream.cxx
new file mode 100644
index 000000000..3f624cfef
--- /dev/null
+++ b/src/input/BufferingInputStream.cxx
@@ -0,0 +1,213 @@
+/*
+ * Copyright 2003-2019 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 "BufferingInputStream.hxx"
+#include "thread/Cond.hxx"
+#include "thread/Name.hxx"
+
+#include <string.h>
+
+BufferingInputStream::BufferingInputStream(InputStreamPtr _input)
+ :input(std::move(_input)),
+ mutex(input->mutex),
+ thread(BIND_THIS_METHOD(RunThread)),
+ buffer(input->GetSize())
+{
+ input->SetHandler(this);
+
+ thread.Start();
+}
+
+BufferingInputStream::~BufferingInputStream() noexcept
+{
+ {
+ const std::lock_guard<Mutex> lock(mutex);
+ stop = true;
+ wake_cond.notify_one();
+ }
+
+ thread.Join();
+}
+
+void
+BufferingInputStream::Check()
+{
+ if (input)
+ input->Check();
+}
+
+void
+BufferingInputStream::Seek(std::unique_lock<Mutex> &lock, size_t new_offset)
+{
+ if (new_offset >= size()) {
+ offset = new_offset;
+ return;
+ }
+
+ auto r = buffer.Read(new_offset);
+ if (r.HasData()) {
+ /* nice, we already have some data at the desired
+ offset and this method call is a no-op */
+ offset = new_offset;
+ return;
+ }
+
+ seek_offset = new_offset;
+ seek = true;
+ wake_cond.notify_one();
+
+ client_cond.wait(lock, [this]{ return !seek; });
+
+ if (seek_error)
+ std::rethrow_exception(std::exchange(seek_error, {}));
+
+ offset = new_offset;
+}
+
+bool
+BufferingInputStream::IsAvailable() noexcept
+{
+ return offset == size() || buffer.Read(offset).HasData();
+}
+
+size_t
+BufferingInputStream::Read(std::unique_lock<Mutex> &lock, void *ptr, size_t s)
+{
+ if (offset >= size())
+ return 0;
+
+ while (true) {
+ auto r = buffer.Read(offset);
+ if (r.HasData()) {
+ /* yay, we have some data */
+ size_t nbytes = std::min(s, r.defined_buffer.size);
+ memcpy(ptr, r.defined_buffer.data, nbytes);
+ offset += nbytes;
+
+ if (!IsAvailable()) {
+ /* wake up the sleeping thread */
+ idle = false;
+ wake_cond.notify_one();
+ }
+
+ return nbytes;
+ }
+
+ if (read_error) {
+ wake_cond.notify_one();
+ std::rethrow_exception(std::exchange(read_error, {}));
+ }
+
+ if (idle) {
+ /* wake up the sleeping thread */
+ idle = false;
+ wake_cond.notify_one();
+ }
+
+ client_cond.wait(lock);
+ }
+}
+
+void
+BufferingInputStream::RunThread() noexcept
+{
+ SetThreadName("input_buffered");
+
+ std::unique_lock<Mutex> lock(mutex);
+
+ while (!stop) {
+ if (seek) {
+ try {
+ input->Seek(lock, seek_offset);
+ } catch (...) {
+ seek_error = std::current_exception();
+ }
+
+ idle = false;
+ seek = false;
+ client_cond.notify_one();
+ } else if (!idle && !read_error &&
+ offset != input->GetOffset() &&
+ !IsAvailable()) {
+ /* a past Seek() call was a no-op because data
+ was already available at that position, but
+ now we've reached a new position where
+ there is no more data in the buffer, and
+ our input is reading somewhere else (maybe
+ stuck at the end of the file); to find a
+ way out, we now seek our input to our
+ reading position to be able to fill our
+ buffer */
+
+ try {
+ input->Seek(lock, offset);
+ } catch (...) {
+ /* this is really a seek error, but we
+ register it as a read_error,
+ because seek_error is only checked
+ by Seek(), and at our frontend (our
+ own InputStream interface) is in
+ "read" mode */
+ read_error = std::current_exception();
+ }
+ } else if (!idle && !read_error &&
+ input->IsAvailable() && !input->IsEOF()) {
+ const auto read_offset = input->GetOffset();
+ auto w = buffer.Write(read_offset);
+
+ if (w.empty()) {
+ if (IsAvailable()) {
+ /* we still have enough data
+ for the next Read() - sleep
+ until we need more data */
+ idle = true;
+ } else {
+ /* we need more data at our
+ current position, because
+ the next Read() will stall
+ - seek our input to our
+ offset to prepare filling
+ the buffer from there */
+ try {
+ input->Seek(lock, offset);
+ } catch (...) {
+ read_error = std::current_exception();
+ client_cond.notify_one();
+ OnBufferAvailable();
+ }
+ }
+
+ continue;
+ }
+
+ try {
+ size_t nbytes = input->Read(lock,
+ w.data, w.size);
+ buffer.Commit(read_offset,
+ read_offset + nbytes);
+ } catch (...) {
+ read_error = std::current_exception();
+ }
+
+ client_cond.notify_one();
+ OnBufferAvailable();
+ } else
+ wake_cond.wait(lock);
+ }
+}
diff --git a/src/input/BufferingInputStream.hxx b/src/input/BufferingInputStream.hxx
new file mode 100644
index 000000000..6749022a5
--- /dev/null
+++ b/src/input/BufferingInputStream.hxx
@@ -0,0 +1,100 @@
+/*
+ * Copyright 2003-2019 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_BUFFERING_INPUT_STREAM_BUFFER_HXX
+#define MPD_BUFFERING_INPUT_STREAM_BUFFER_HXX
+
+#include "InputStream.hxx"
+#include "Ptr.hxx"
+#include "Handler.hxx"
+#include "thread/Thread.hxx"
+#include "thread/Cond.hxx"
+#include "util/SparseBuffer.hxx"
+
+#include <exception>
+
+/**
+ * A "huge" buffer which remembers the (partial) contents of an
+ * #InputStream. This works only if the #InputStream is a "file", not
+ * a "stream".
+ */
+class BufferingInputStream : InputStreamHandler {
+ InputStreamPtr input;
+
+ Mutex &mutex;
+
+ Thread thread;
+
+ /**
+ * This #Cond wakes up the #Thread. It is used by both the
+ * "client" thread (to submit commands) and #input's handler
+ * (to notify new data being available).
+ */
+ Cond wake_cond;
+
+ /**
+ * This #Cond wakes up the client upon command completion.
+ */
+ Cond client_cond;
+
+ SparseBuffer<uint8_t> buffer;
+
+ bool stop = false, seek = false, idle = false;
+
+ size_t offset = 0;
+
+ size_t seek_offset;
+
+ std::exception_ptr read_error, seek_error;
+
+public:
+ explicit BufferingInputStream(InputStreamPtr _input);
+ ~BufferingInputStream() noexcept;
+
+ const auto &GetInput() const noexcept {
+ return *input;
+ }
+
+ auto size() const noexcept {
+ return buffer.size();
+ }
+
+ void Check();
+ void Seek(std::unique_lock<Mutex> &lock, size_t new_offset);
+ bool IsAvailable() noexcept;
+ size_t Read(std::unique_lock<Mutex> &lock, void *ptr, size_t size);
+
+protected:
+ virtual void OnBufferAvailable() noexcept {}
+
+private:
+ void RunThread() noexcept;
+
+ /* virtual methods from class InputStreamHandler */
+ void OnInputStreamReady() noexcept final {
+ /* this should never be called, because our input must
+ be "ready" already */
+ }
+
+ void OnInputStreamAvailable() noexcept final {
+ wake_cond.notify_one();
+ }
+};
+
+#endif
diff --git a/src/input/meson.build b/src/input/meson.build
index 2ce6f8832..3502379d8 100644
--- a/src/input/meson.build
+++ b/src/input/meson.build
@@ -32,6 +32,7 @@ input_glue = static_library(
'TextInputStream.cxx',
'ProxyInputStream.cxx',
'RewindInputStream.cxx',
+ 'BufferingInputStream.cxx',
'BufferedInputStream.cxx',
'MaybeBufferedInputStream.cxx',
include_directories: inc,