Chromium.googlesource.com

Intent

A one-to-many dependency between object so that when one object (subject) changes, all its dependents (observers) are notified and update automatically.

Dependency Inversion Principle

Your code should depend on abstractions, not concrete implementations. Instead of:

public class EmailSender
{
  public void Send(string message) { ... }
}

public class NotificationService
{
  private readonly EmailSender _emailSender = new();

  public void Notify(string message) => _emailSender.Send(message);
}

… have:

public interface IMessageSender
{
  void Send(string message);
}

public class EmailMessageSender : IMessageSender
{
  public void Send(string message) { ... }
}

public class NotificationService(IMessageSender messageSender)
{
  public void Notify(string message) => messageSender.Send(message);
}

… so that swapping out an EmailMessageSender for an SmsMessageSender is easy. Even more commonly, unit testing NotificationService with a MockMessageSender that doesn’t send real messages.

Notes from Chromium

Phrased differently, inversion of control allows users of a framework/library (clients) to customize the behavior of the framework. The control flow is inverted because the library (e.g., NotificationService) calls back into the client’s code (e.g., the specific IMessageSender implementation) so that control flows back from a low-level class to a high-level class. .

Performance in Context

The execution of a web browser primarily involves three tasks: fetching resources, page layout and rendering, and JavaScript execution. That said, optimizing the last two tasks won’t do much good if the browser is blocked on the network, waiting for resources to arrive.

Of the top 100K, the median page on desktop requests 97 resources weighing 2,954KB in total, and makes 16 TCP connections . While the underlying transport (TCP) is optimized for large, streaming downloads, most network transfers in the browser are short and bursty.

Stability, Testing and the Multi-Process Architecture

In a single-threaded browser, devs use asynchronous APIs - which may sometimes hold the browser up. Instead of multiple threads, Chromium chose multiple processes: isolation, independent crashes, better asymptotic memory management, identifying expensive sites, etc.

The Dilemma

There are wide productivity variations between good programmers and poor ones. Sackman et. al. found 10:1 ratios. The data showed no correlation between experience and performance.

The major part of the cost of large teams is communication, and system debugging to correct the ill effects of miscommunication.

One can use curl -v <url> to see all of the redirections and cookies set. found that generating a tiny URL for Zoom links gives a URL that first goes to redirect.viglink.com.

proposes Federated Learning of Cohorts, which aims to enable ad-targeting based on people’s general browsing interest without exposing the exact browsing history.

Unscoped (or Plain or C-Style) Enumerations

Plain (or C-style) enums are entered in the same scope as the name of their enum, and implicitly convert to their integer value, e.g.

enum Color { red, green, blue };
int col = green;
Color c2 = 1; // error: invalid conversion from 'int' to 'Color' [-fpermissive]

enum CardColor { red, black }; // Error: "red" conflicts with a previous declaration

The name can be omitted if it’s not going to be used, e.g.

enum { red, green, blue };
int col = red;

.

Unnamed enums are common in code written before alternative ways of specifying integer constants, e.g.