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Diffstat (limited to 'src/filter/plugins/ChainFilterPlugin.cxx')
| -rw-r--r-- | src/filter/plugins/ChainFilterPlugin.cxx | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/src/filter/plugins/ChainFilterPlugin.cxx b/src/filter/plugins/ChainFilterPlugin.cxx new file mode 100644 index 000000000..7dc6db667 --- /dev/null +++ b/src/filter/plugins/ChainFilterPlugin.cxx @@ -0,0 +1,181 @@ +/* + * 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 "ChainFilterPlugin.hxx" +#include "filter/FilterPlugin.hxx" +#include "filter/FilterInternal.hxx" +#include "filter/FilterRegistry.hxx" +#include "AudioFormat.hxx" +#include "util/Error.hxx" +#include "util/Domain.hxx" + +#include <list> + +#include <assert.h> + +class ChainFilter final : public Filter { + struct Child { + const char *name; + Filter *filter; + + Child(const char *_name, Filter *_filter) + :name(_name), filter(_filter) {} + ~Child() { + delete filter; + } + + Child(const Child &) = delete; + Child &operator=(const Child &) = delete; + }; + + std::list<Child> children; + +public: + void Append(const char *name, Filter *filter) { + children.emplace_back(name, filter); + } + + virtual AudioFormat Open(AudioFormat &af, Error &error) override; + virtual void Close(); + virtual const void *FilterPCM(const void *src, size_t src_size, + size_t *dest_size_r, Error &error); + +private: + /** + * Close all filters in the chain until #until is reached. + * #until itself is not closed. + */ + void CloseUntil(const Filter *until); +}; + +static constexpr Domain chain_filter_domain("chain_filter"); + +static Filter * +chain_filter_init(gcc_unused const config_param ¶m, + gcc_unused Error &error) +{ + return new ChainFilter(); +} + +void +ChainFilter::CloseUntil(const Filter *until) +{ + for (auto &child : children) { + if (child.filter == until) + /* don't close this filter */ + return; + + /* close this filter */ + child.filter->Close(); + } + + /* this assertion fails if #until does not exist (anymore) */ + assert(false); + gcc_unreachable(); +} + +static AudioFormat +chain_open_child(const char *name, Filter *filter, + const AudioFormat &prev_audio_format, + Error &error) +{ + AudioFormat conv_audio_format = prev_audio_format; + const AudioFormat next_audio_format = + filter->Open(conv_audio_format, error); + if (!next_audio_format.IsDefined()) + return next_audio_format; + + if (conv_audio_format != prev_audio_format) { + struct audio_format_string s; + + filter->Close(); + + error.Format(chain_filter_domain, + "Audio format not supported by filter '%s': %s", + name, + audio_format_to_string(prev_audio_format, &s)); + return AudioFormat::Undefined(); + } + + return next_audio_format; +} + +AudioFormat +ChainFilter::Open(AudioFormat &in_audio_format, Error &error) +{ + AudioFormat audio_format = in_audio_format; + + for (auto &child : children) { + audio_format = chain_open_child(child.name, child.filter, + audio_format, error); + if (!audio_format.IsDefined()) { + /* rollback, close all children */ + CloseUntil(child.filter); + break; + } + } + + /* return the output format of the last filter */ + return audio_format; +} + +void +ChainFilter::Close() +{ + for (auto &child : children) + child.filter->Close(); +} + +const void * +ChainFilter::FilterPCM(const void *src, size_t src_size, + size_t *dest_size_r, Error &error) +{ + for (auto &child : children) { + /* feed the output of the previous filter as input + into the current one */ + src = child.filter->FilterPCM(src, src_size, &src_size, + error); + if (src == nullptr) + return nullptr; + } + + /* return the output of the last filter */ + *dest_size_r = src_size; + return src; +} + +const struct filter_plugin chain_filter_plugin = { + "chain", + chain_filter_init, +}; + +Filter * +filter_chain_new(void) +{ + return new ChainFilter(); +} + +void +filter_chain_append(Filter &_chain, const char *name, Filter *filter) +{ + ChainFilter &chain = (ChainFilter &)_chain; + + chain.Append(name, filter); +} |