This sample implements a minimal source control provider. It shows how the source control experience in VS Code could be used to for example interact with code in JSFiddle.

Following VS Code APIs are demonstrated by this extension:

• workspace.workspaceFolders
• scm.createSourceControl
• SourceControl
• SourceControlResourceGroup
• TextDocumentContentProvider

Activate the extension by invoking the Open JSFiddle command, specify the JSFiddle code, if no workspace folder is open, select a workspace folder. This invokes following 4 lines, which does the following:

1. creates the custom source control provider associated with the workspace folder
2. creates the source control resource group to later show the local changes to the files in the repository
3. registers the quickDiffProvider, which implements the mapping between the documents in the remote repository and documents in the local folder.

this.jsFiddleScm = vscode.scm.createSourceControl('jsfiddle', 'JSFiddle #' + fiddle.slug, workspaceFolder.uri);
this.changedResources = this.jsFiddleScm.createResourceGroup('workingTree', 'Changes');
this.fiddleRepository = new FiddleRepository(workspaceFolder, fiddle.slug);
this.jsFiddleScm.quickDiffProvider = this.fiddleRepository;

See fiddleSourceControl.ts for full code listing.

The three commands (command, roll-back and refresh) in the title of the source control view pane are configured this way:

"contributes": {
    "commands": [
        ...
    ],
    "menus": {
        "scm/title": [
            {
                "command": "extension.source-control.commit",
                "group": "navigation",
                "when": "scmProvider == jsfiddle"
            },
            {
                "command": "extension.source-control.discard",
                "group": "navigation",
                "when": "scmProvider == jsfiddle"
            },
            {
                "command": "extension.source-control.refresh",
                "group": "navigation",
                "when": "scmProvider == jsfiddle"
            },
            {
                "command": "extension.source-control.browse",
                "when": "scmProvider == jsfiddle"
            }
        ]
    }
},

Note that the extension.source-control.browse command is intentionally missing the "group": "navigation" placement specification, which makes it show up under the [dot dot dot] button.

It is also worth noting that the sample extension needs to overcome reloading that VS Code triggers when a new workspace folder is added. This could be done either by writing a memo into the context.globalState, or a configuration file into the workspace folder and reading it upon the next extension activation. The selected solution is to use .jsfiddle configuration file as described below.

The custom source control can add its own controls to the status bar. This typically needs to be refreshed every time a new version/branch is checked-out.

this.jsFiddleScm.statusBarCommands = [
    {
        "command": "extension.source-control.checkout",
        "title": `↕ ${this.fiddle.slug} #${this.fiddle.version} / ${this.latestFiddleVersion}`,
        "tooltip": "Checkout another version of this fiddle.",
    }
];

The command extension.source-control.checkout displays quick pick of the JSFiddle versions to check-out.

The extension listens to changes to files in the workspace folder and compares the new document text to the version originally checked out from the repository. When it differs, it creates vscode.SourceControlResourceState for every changed document assigns such list to this.changedResources.resourceStates, where the this.changedResources was created earlier.

{
    resourceUri: doc.uri,
    command: {
        title: "Show changes",
        command: "vscode.diff",
        arguments: [repositoryUri, doc.uri, `Checked-out version ↔ Local changes`],
        tooltip: "Diff your changes"
    }
}

where repositoryUri is determined by

this.fiddleRepository.provideOriginalResource(doc.uri, null)

Both the regular diff (invoking the built-in vscode.diff when user clicks on the changed resource in the source control view) and the Quick Diff (available in the left margin of the text editor) are rendered automatically by VS Code as long as the extension provides it with the content of the original document checked out from the repository. This is done by implementing a TextDocumentContentProvider.

A source control extensions gets activated either when a remote repository gets cloned upon user request, or when a previously cloned workspace folder is open.

    "activationEvents": [
        "workspaceContains:.jsfiddle"
    ],

This extension implements the cloning using the extension.source-control.open command.

This sample extension stores the source control configuration in the .jsfiddle JSON file in the workspace folder root.

This is done by storing the .jsfiddle configuration file into the WorkspaceFolder just inserting the workspace folder via the vscode.workspace.updateWorkspaceFolders(...) call, which seems to make the extension re-activate. Upon the re-activation, the initializeFromConfigurationFile() function scans all WorkspaceFolders for the .jsfiddle configuration files and re-creates the SourceControl instances.

Source control extension should support multiple workspace folders bound to different remote repositories.

This sample can be tested on any JSFiddle with (e.g. u8B29/1) or without (e.g. u8B29) the version number specified. However, if you want to test committing code back to the repository, try typing in demo instead of a real fiddle name, which lets you mock the repository without reading/writing from/to actual JSFiddle.