src/goDeclaration.ts

/*---------------------------------------------------------
 * Copyright (C) Microsoft Corporation. All rights reserved.
 *--------------------------------------------------------*/

'use strict';

import vscode = require('vscode');
import cp = require('child_process');
import path = require('path');
import {getBinPath} from './goPath'

export class GoDefinitionProvider implements vscode.DefinitionProvider {

	public provideDefinition(document:vscode.TextDocument, position:vscode.Position, token: vscode.CancellationToken):Thenable<vscode.Location> {

		return new Promise((resolve, reject) => {

			var wordAtPosition = document.getWordRangeAtPosition(position);
			var offset = document.offsetAt(position);

			var godef = getBinPath("godef");

			// Spawn `godef` process
			var p = cp.execFile(godef, ["-t", "-i", "-f", document.fileName, "-o", offset.toString()], {}, (err, stdout, stderr) => {
				try {
					if (err && (<any>err).code == "ENOENT") {
						vscode.window.showInformationMessage("The 'godef' command is not available.  Use 'go get -u github.com/rogpeppe/godef' to install.");
					}
					if (err) return resolve(null);
					var result = stdout.toString();
					var lines = result.split('\n');
					// TODO: Goto def on a package name import will return juts a plain
					// path to a folder here - can we go to a folder?
					var match = /(.*):(\d+):(\d+)/.exec(lines[0]);
					if(!match) return resolve(null);
					var [_, file, line, col] = match;
					var definitionResource = vscode.Uri.file(file);
					var range = new vscode.Range(+line-1, +col-1, +line-1, +col-1);
					return resolve(
						new vscode.Location(definitionResource, range)
					);
				} catch(e) {
					reject(e);
				}
			});
			p.stdin.end(document.getText());
		});
	}
}