GstPipelineStudio/src/pipeline.rs

// pipeline.rs
//
// Copyright 2021 Stéphane Cerveau <scerveau@collabora.com>
//
// 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 3 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, see <http://www.gnu.org/licenses/>.
//
// SPDX-License-Identifier: GPL-3.0-only
use gst::prelude::*;
use gstreamer as gst;
use std::error;

#[derive(Debug, Eq, Ord, PartialEq, PartialOrd)]
pub struct ElementInfo {
    pub name: Option<String>,
    plugin_name: Option<String>,
    rank: i32,
}

impl Default for ElementInfo {
    fn default() -> ElementInfo {
        ElementInfo {
            name: None,
            plugin_name: None,
            rank: -1,
        }
    }
}

pub struct Pipeline {
    initialized: bool,
}

impl Default for Pipeline {
    fn default() -> Pipeline {
        Pipeline { initialized: false }
    }
}

impl Pipeline {
    pub fn new() -> Result<Self, Box<dyn error::Error>> {
        gst::init()?;
        Ok(Self { initialized: true })
    }

    pub fn elements_list() -> Result<Vec<ElementInfo>, Box<dyn error::Error>> {
        let registry = gst::Registry::get();
        let mut elements: Vec<ElementInfo> = Vec::new();
        let plugins = gst::Registry::get_plugin_list(&registry);
        for plugin in plugins {
            let plugin_name = gst::Plugin::get_plugin_name(&plugin);
            let features = gst::Registry::get_feature_list_by_plugin(&registry, &plugin_name);
            for feature in features {
                let mut element = ElementInfo::default();
                if let Ok(factory) = feature.downcast::<gst::ElementFactory>() {
                    let feature = factory.upcast::<gst::PluginFeature>();

                    element.name = Some(gst::PluginFeature::get_name(&feature).as_str().to_owned());
                    element.plugin_name =
                        Some(gst::Plugin::get_plugin_name(&plugin).as_str().to_owned());
                    elements.push(element);
                }
            }
        }
        Ok(elements)
    }
}