shadercached/src/service/signal.rs

// Copyright 2023 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Collections of methods to send D-BUS signals

use crate::dbus_constants;
use anyhow::{anyhow, Result};
use dbus::{channel::Sender, nonblock::SyncConnection};
use libchromeos::sys::debug;
use std::sync::Arc;
use system_api::shadercached::ShaderCacheMountStatus;

pub fn signal_mount_status(
    mount_status_many: Vec<ShaderCacheMountStatus>,
    conn: &Arc<SyncConnection>,
) -> Result<()> {
    let mut errors: Vec<String> = vec![];
    for status in mount_status_many {
        if let Err(e) = emit_signal(&status, dbus_constants::MOUNT_STATUS_CHANGED_SIGNAL, conn) {
            errors.push(e.to_string());
        }
    }

    if errors.is_empty() {
        Ok(())
    } else {
        Err(anyhow!("Failed to signal some status: {:?}", errors))
    }
}

fn emit_signal(
    to_emit: &dyn protobuf::Message,
    signal_name: &str,
    conn: &Arc<SyncConnection>,
) -> Result<()> {
    // Tell Cicerone shader cache has been (un)mounted, so that it can continue
    // process calls.
    let mounted_signal = dbus::Message::new_signal(
        dbus_constants::PATH_NAME,
        dbus_constants::INTERFACE_NAME,
        signal_name,
    )
    .map_err(|e| anyhow!("Failed to create signal: {}", e))?
    .append1(
        to_emit
            .write_to_bytes()
            .map_err(|e| anyhow!("Failed to parse protobuf: {}", e))?,
    );
    debug!("Sending {} signal.. {:?}", signal_name, to_emit);
    conn.send(mounted_signal)
        .map_err(|_| anyhow!("Failed to send signal"))?;
    Ok(())
}