src/log_view.ts

// Copyright 2024 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import * as vscode from 'vscode';

import { Ffx, FuchsiaDevice } from './ffx';
import { DataStreamProcess } from './process';

export class LogView {
  private deviceName?: string;
  private deviceConnected?: boolean;
  private logProcess?: DataStreamProcess;
  public output?: vscode.OutputChannel;

  constructor(readonly ffx: Ffx) {
    ffx.onSetTarget(target => { this.watch(target); });
  }

  watch(device: FuchsiaDevice | null) {
    let targetDeviceName = device?.nodeName;
    let targetDeviceConnected = device?.connected ?? false;
    if (targetDeviceName === this.deviceName && targetDeviceConnected === this.deviceConnected) {
      // Already watching this device.
      return;
    }
    this.deviceName = targetDeviceName;
    this.deviceConnected = targetDeviceConnected;

    if (this.logProcess) {
      this.logProcess.stop();
      this.logProcess = undefined;
    }

    if (!targetDeviceConnected) {
      if (this.output) {
        this.output.appendLine('=== Device disconnected ===');
      } else {
        this.createOutputChannel();
        this.output!.appendLine('=== No device connected ===');
      }
      return;
    }

    if (this.output) {
      this.output.clear();
    } else {
      this.createOutputChannel();
    }

    let self = this;

    /**
     * handle stdout and stderr output from the log process
     * The data is appended to the output channel.
     * @param buffer the data received from the log process
     */
    function handleData(buffer: Buffer) {
      const messages = new TextDecoder().decode(buffer);
      self.output?.append(messages);
    }

    let args = ['log', '--no-color'];
    if (this.deviceName) {
      args = ['--target', this.deviceName, ...args];
    }
    this.logProcess = this.ffx.runFfxAsync(args, handleData, handleData);
  }

  createOutputChannel() {
    this.output = vscode.window.createOutputChannel('Fuchsia Logs', 'fuchsia-log');
  }
}