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Commit 83baba50 authored by James Shargo's avatar James Shargo
Browse files

libbufferstreams: Add a StreamConfig type (and associated trait methods)

This type will be used to create publishers and subscribers, and
contains enough information to create AHardwareBuffers.

Bug: 296100790, 296450062
Test: atest libbufferstreams-internal_test
Change-Id: I12a2aa59e8931ab77c658371d16450f3618de8ce
parent 667e31ac
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+17 −5
Original line number Diff line number Diff line
@@ -12,13 +12,25 @@
// See the License for the specific language governing permissions and
// limitations under the License.

rust_library {
    name: "libbufferstreams",
    crate_name: "bufferstreams",
rust_defaults {
    name: "libbufferstreams_defaults",
    srcs: ["src/lib.rs"],
    edition: "2021",
    rlibs: [
    rustlibs: [
        "libnativewindow_rs",
    ],
    edition: "2021",
}

rust_library {
    name: "libbufferstreams",
    crate_name: "bufferstreams",
    defaults: ["libbufferstreams_defaults"],
    min_sdk_version: "30",
}

rust_test {
    name: "libbufferstreams-internal_test",
    crate_name: "bufferstreams",
    defaults: ["libbufferstreams_defaults"],
    test_suites: ["general-tests"],
}
+8 −0
Original line number Diff line number Diff line
@@ -14,6 +14,10 @@

//! libbufferstreams: Reactive Streams for Graphics Buffers

mod stream_config;

pub use stream_config::*;

use nativewindow::*;
use std::sync::{Arc, Weak};
use std::time::Instant;
@@ -50,6 +54,8 @@ pub extern "C" fn hello() -> bool {
/// *  A Publisher MAY support multiple Subscribers and decides whether each
/// Subscription is unicast or multicast.
pub trait BufferPublisher {
    /// Returns the StreamConfig of buffers that publisher creates.
    fn get_publisher_stream_config(&self) -> StreamConfig;
    /// This function will create the subscription between the publisher and
    /// the subscriber.
    fn subscribe(&self, subscriber: Weak<dyn BufferSubscriber>);
@@ -82,6 +88,8 @@ pub trait BufferPublisher {
/// *   A Publisher MAY support multiple Subscribers and decides whether each
/// Subscription is unicast or multicast.
pub trait BufferSubscriber {
    /// The StreamConfig of buffers that this subscriber expects.
    fn get_subscriber_stream_config(&self) -> StreamConfig;
    /// This function will be called at the beginning of the subscription.
    fn on_subscribe(&self, subscription: Arc<dyn BufferSubscription>);
    /// This function will be called for buffer that comes in.
+67 −0
Original line number Diff line number Diff line
// Copyright (C) 2023 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use nativewindow::*;

/// The configuration of the buffers published by a [BufferPublisher] or
/// expected by a [BufferSubscriber].
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct StreamConfig {
    /// Width in pixels of streaming buffers.
    pub width: u32,
    /// Height in pixels of streaming buffers.
    pub height: u32,
    /// Number of layers of streaming buffers.
    pub layers: u32,
    /// Format of streaming buffers.
    pub format: AHardwareBuffer_Format::Type,
    /// Usage of streaming buffers.
    pub usage: AHardwareBuffer_UsageFlags,
    /// Stride of streaming buffers.
    pub stride: u32,
}

impl StreamConfig {
    /// Tries to create a new AHardwareBuffer from settings in a [StreamConfig].
    pub fn create_hardware_buffer(&self) -> Option<AHardwareBuffer> {
        AHardwareBuffer::new(self.width, self.height, self.layers, self.format, self.usage)
    }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test_create_hardware_buffer() {
        let config = StreamConfig {
            width: 123,
            height: 456,
            layers: 1,
            format: AHardwareBuffer_Format::AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM,
            usage: AHardwareBuffer_UsageFlags::AHARDWAREBUFFER_USAGE_CPU_READ_OFTEN
                | AHardwareBuffer_UsageFlags::AHARDWAREBUFFER_USAGE_CPU_WRITE_OFTEN,
            stride: 0,
        };

        let maybe_buffer = config.create_hardware_buffer();
        assert!(maybe_buffer.is_some());

        let buffer = maybe_buffer.unwrap();
        assert_eq!(config.width, buffer.width());
        assert_eq!(config.height, buffer.height());
        assert_eq!(config.format, buffer.format());
        assert_eq!(config.usage, buffer.usage());
    }
}