src/doc_provider.ts

// Copyright 2025 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import * as vscode from 'vscode';
import * as path from 'path';

// Capture Groups | 0:Match | 1: Filepath | 2: Line | 3: Column

// CPP and Rust format of ../../[path]/[file].[extension]:[line]:[column]
const CPP_RUST_MATCHER = /\.\.\/\.\.(\/.*):(\d+):(\d+)/g;

// GN format of //[path].[extension]:[line]:[column]
const GN_MATCHER = /(\/\/.*):(\d+):(\d+)/g;

// Python format of [path].[extension]:[line]
const PY_MATCHER = /(.*.py):(\d+)/g;

/**
 * Provide DocumentLinks for Fuchsia output syntax errors in Fuchsia builds.
 */
export class FuchsiaDocumentLinkProvider implements vscode.DocumentLinkProvider {
  provideDocumentLinks(
    document: vscode.TextDocument,
    token: vscode.CancellationToken
  ): vscode.ProviderResult<vscode.DocumentLink[]> {

    const links: vscode.DocumentLink[] = [];
    const workspaceFolder = vscode.workspace.workspaceFolders;

    if (!workspaceFolder || workspaceFolder[0].name !== 'fuchsia') {
      return [];
    }

    const workspacePath = workspaceFolder[0].uri.fsPath;
    const text = document.getText();

    const matcher = new RegExp(
      `${CPP_RUST_MATCHER.source}|${GN_MATCHER.source}|${PY_MATCHER.source}`,
      'g');
    let matches = text.matchAll(matcher);

    for (const fileMatch of matches) {
      // Remove null items in matcher groups
      const match = fileMatch.filter((item) => !!item);

      const linkText = match[0];
      const filePath = match[1];
      const line = parseInt(match[2]);
      const column = parseInt(match[3]);

      const fullPath = path.join(workspacePath, filePath);
      const fileUri = vscode.Uri.file(fullPath);

      // The range in the document to underline link
      const start = document.positionAt(fileMatch.index!);
      const end = document.positionAt(fileMatch.index! + linkText.length);
      const linkRange = new vscode.Range(start, end);

      // Link format is file:///path/to/file.ts#Lline,column
      const link = new vscode.DocumentLink(
        linkRange,
        fileUri.with({ fragment: `L${line},${column}` })
      );
      link.tooltip =
        `Go to line ${line}${isNaN(column) ? '' : `:${column}`} in ${path.basename(filePath)}`;
      links.push(link);
    }
    return links;
  }
}