186 lines
7.3 KiB
Markdown
186 lines
7.3 KiB
Markdown
# Glossary
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This page defines some terminology that is commonly used in Electron development.
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### ASAR
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ASAR stands for Atom Shell Archive Format. An [asar][asar] archive is a simple
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`tar`-like format that concatenates files into a single file. Electron can read
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arbitrary files from it without unpacking the whole file.
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The ASAR format was created primarily to improve performance on Windows... TODO
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### CRT
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The C Run-time Library (CRT) is the part of the C++ Standard Library that
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incorporates the ISO C99 standard library. The Visual C++ libraries that
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implement the CRT support native code development, and both mixed native and
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managed code, and pure managed code for .NET development.
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### DMG
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An Apple Disk Image is a packaging format used by macOS. DMG files are
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commonly used for distributing application "installers". [electron-builder]
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supports `dmg` as a build target.
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### IME
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Input Method Editor. A program that allows users to enter characters and
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symbols not found on their keyboard. For example, this allows users of Latin
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keyboards to input Chinese, Japanese, Korean and Indic characters.
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### IDL
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Interface description language. Write function signatures and data types in a format that can be used to generate interfaces in Java, C++, JavaScript, etc.
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### IPC
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IPC stands for Inter-Process Communication. Electron uses IPC to send
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serialized JSON messages between the [main] and [renderer] processes.
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### libchromiumcontent
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A shared library that includes the [Chromium Content module] and all its
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dependencies (e.g., Blink, [V8], etc.). Also referred to as "libcc".
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- [github.com/electron/libchromiumcontent](https://github.com/electron/libchromiumcontent)
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### main process
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The main process, commonly a file named `main.js`, is the entry point to every
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Electron app. It controls the life of the app, from open to close. It also
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manages native elements such as the Menu, Menu Bar, Dock, Tray, etc. The
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main process is responsible for creating each new renderer process in the app.
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The full Node API is built in.
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Every app's main process file is specified in the `main` property in
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`package.json`. This is how `electron .` knows what file to execute at startup.
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In Chromium, this process is referred to as the "browser process". It is
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renamed in Electron to avoid confusion with renderer processes.
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See also: [process](#process), [renderer process](#renderer-process)
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### MAS
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Acronym for Apple's Mac App Store. For details on submitting your app to the
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MAS, see the [Mac App Store Submission Guide].
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### Mojo
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An IPC system for communicating intra- or inter-process, and that's important because Chrome is keen on being able to split its work into separate processes or not, depending on memory pressures etc.
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See https://chromium.googlesource.com/chromium/src/+/master/mojo/README.md
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### native modules
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Native modules (also called [addons] in
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Node.js) are modules written in C or C++ that can be loaded into Node.js or
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Electron using the require() function, and used as if they were an
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ordinary Node.js module. They are used primarily to provide an interface
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between JavaScript running in Node.js and C/C++ libraries.
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Native Node modules are supported by Electron, but since Electron is very
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likely to use a different V8 version from the Node binary installed in your
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system, you have to manually specify the location of Electron’s headers when
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building native modules.
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See also [Using Native Node Modules].
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### NSIS
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Nullsoft Scriptable Install System is a script-driven Installer
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authoring tool for Microsoft Windows. It is released under a combination of
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free software licenses, and is a widely-used alternative to commercial
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proprietary products like InstallShield. [electron-builder] supports NSIS
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as a build target.
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### OSR
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OSR (Off-screen rendering) can be used for loading heavy page in
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background and then displaying it after (it will be much faster).
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It allows you to render page without showing it on screen.
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### process
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A process is an instance of a computer program that is being executed. Electron
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apps that make use of the [main] and one or many [renderer] process are
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actually running several programs simultaneously.
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In Node.js and Electron, each running process has a `process` object. This
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object is a global that provides information about, and control over, the
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current process. As a global, it is always available to applications without
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using require().
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See also: [main process](#main-process), [renderer process](#renderer-process)
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### renderer process
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The renderer process is a browser window in your app. Unlike the main process,
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there can be multiple of these and each is run in a separate process.
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They can also be hidden.
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In normal browsers, web pages usually run in a sandboxed environment and are not
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allowed access to native resources. Electron users, however, have the power to
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use Node.js APIs in web pages allowing lower level operating system
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interactions.
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See also: [process](#process), [main process](#main-process)
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### Squirrel
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Squirrel is an open-source framework that enables Electron apps to update
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automatically as new versions are released. See the [autoUpdater] API for
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info about getting started with Squirrel.
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### userland
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This term originated in the Unix community, where "userland" or "userspace"
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referred to programs that run outside of the operating system kernel. More
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recently, the term has been popularized in the Node and npm community to
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distinguish between the features available in "Node core" versus packages
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published to the npm registry by the much larger "user" community.
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Like Node, Electron is focused on having a small set of APIs that provide
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all the necessary primitives for developing multi-platform desktop applications.
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This design philosophy allows Electron to remain a flexible tool without being
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overly prescriptive about how it should be used. Userland enables users to
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create and share tools that provide additional functionality on top of what is
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available in "core".
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### V8
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V8 is Google's open source JavaScript engine. It is written in C++ and is
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used in Google Chrome. V8 can run standalone, or can be embedded into any C++ application.
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Electron builds V8 as part of Chromium and then points Node to that V8 when
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building it.
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V8's version numbers always correspond to those of Google Chrome. Chrome 59
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includes V8 5.9, Chrome 58 includes V8 5.8, etc.
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- [developers.google.com/v8](https://developers.google.com/v8)
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- [nodejs.org/api/v8.html](https://nodejs.org/api/v8.html)
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- [docs/development/v8-development.md](development/v8-development.md)
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### webview
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`webview` tags are used to embed 'guest' content (such as external web pages) in
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your Electron app. They are similar to `iframe`s, but differ in that each
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webview runs in a separate process. It doesn't have the same
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permissions as your web page and all interactions between your app and
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embedded content will be asynchronous. This keeps your app safe from the
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embedded content.
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[addons]: https://nodejs.org/api/addons.html
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[asar]: https://github.com/electron/asar
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[autoUpdater]: api/auto-updater.md
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[Chromium Content module]: https://www.chromium.org/developers/content-module
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[electron-builder]: https://github.com/electron-userland/electron-builder
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[libchromiumcontent]: #libchromiumcontent
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[Mac App Store Submission Guide]: tutorial/mac-app-store-submission-guide.md
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[main]: #main-process
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[renderer]: #renderer-process
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[userland]: #userland
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[Using Native Node Modules]: tutorial/using-native-node-modules.md
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[V8]: #v8
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