Displaying local instead of web docs can have many benefits:
- the web version may have different features enabled than locally selected
- the standard library may be a different version than is available online
- the user may not be online and therefore cannot access the web documentation
- the documentation may not be available online at all, for example because it
is for a new feature in a library the user is currently developing
If the documentation is not available locally, the extension still falls back to
the web version.
According to the VS Code documentation, the vscode.open command opens the URL
_in the editor_ (https://code.visualstudio.com/api/references/commands).
However, in reality, it seems to do so only for file:// URLs, falling back to
other applications for other URL schemes (at least for HTTP/HTTPS).
Until now, the URL to the documentation was always HTTP based, so using the
vscode.open command was perfectly fine. However, displaying local documentation
will be supported from now on (see next commit). Local documentation is not
HTTP-based, but instead addressed via a file:// URL. The file URL would
therefore be opened in VS Code instead of in the browser — this is definitely
not what the user wants.
Therefore, the vscode.env.openExternal function is used instead, this function
never opens the URL in VS Code.
This feature requires the user to add a command that generates a
`rust-project.json` from a set of files. Project discovery can be invoked
in two ways:
1. At extension activation time, which includes the generated
`rust-project.json` as part of the linkedProjects argument in
InitializeParams
2. Through a new command titled "Add current file to workspace", which
makes use of a new, rust-analyzer specific LSP request that adds
the workspace without erasing any existing workspaces.
I think that the command-running functionality _could_ merit being
placed into its own extension (and expose it via extension contribution
points), if only provide build-system idiomatic progress reporting and
status handling, but I haven't (yet) made an extension that does this.
