SI Search

A Source Insight-style code search extension for VS Code, designed for C/C++ developers working on large-scale codebases.

SI Search builds a symbol index using tree-sitter parsing, enabling instant symbol lookup across your entire workspace. When the index doesn't cover a query, it falls back to ripgrep full-text search seamlessly.

Features

Symbol Index (Sync)

SI Search uses tree-sitter (WASM) to parse all C/C++ source files in your workspace and extract symbol definitions:

• Functions — int main(), void foo()
• Structs — struct device
• Enums — enum state
• Typedefs — typedef unsigned int uint32_t
• Macros — #define MAX_SIZE 1024, #define INIT(x) ...
• Classes (C++) — class Widget
• Namespaces (C++) — namespace std
• Unions — union data

The index is persisted to disk (.sisearch/index.json in the workspace root) and automatically restored on VS Code restart—no re-scanning needed.

Press Ctrl+Shift+S or click the sync button in the Search panel title bar to build/update the index.

Two-Tier Search Strategy

1. Index search (instant) — When the symbol index is ready, queries are matched against the in-memory index with O(1) exact lookup or fast substring/regex scan.
2. Ripgrep fallback — If the index has no results (e.g., searching for a string literal rather than a symbol name), SI Search automatically falls back to ripgrep full-text search.

This hybrid approach gives you the speed of pre-built indexes with the coverage of full-text search.

Search Results Panel

• Syntax-highlighted preview — Hover over any result's code portion to see a multi-line preview with full syntax highlighting (powered by shiki), matching your current VS Code color theme.
• Jump to source — Click the arrow icon on any result to open the file at the exact line.
• Result navigation — Step through results one by one with Ctrl+Shift+F4 / Ctrl+Shift+F3.
• Gutter indicators — Source files that contain search results show blue triangle markers in the editor gutter.
• CodeLens links — "Jump to Search Result" CodeLens appears on matched lines, allowing quick navigation back to the results panel.

Manual Highlights

• Press Ctrl+Shift+F8 to highlight the selected text (or trigger a selection prompt in the results panel).
• Multiple highlight colors cycle automatically.
• Highlights appear both in the results panel and in all open editors.
• The Highlights tree view in the sidebar shows all active highlights with remove buttons.

Incremental File Watching

SI Search monitors your workspace for file changes:

• Modified/created files are marked as dirty; the status bar shows "stale".
• Deleted files are removed from the index.
• Re-sync (Ctrl+Shift+S) only re-parses changed files, not the entire workspace.

Architecture

File System ── SymbolParser (web-tree-sitter WASM) ── SymbolIndex (Memory + Disk)
                                                            |
                                                       SearchEngine
                                                      /           \
                                              Index Search    Ripgrep Fallback

File Watcher ── marks dirty/deleted files ── SymbolIndex

Key components:

Commands

Configuration

All settings are under the siSearch.* namespace in VS Code settings.

Search Options

The search input supports three toggle options:

• Case Sensitive (Aa) — Match exact letter casing.
• Whole Word (W) — Match whole words only (maps to ripgrep --word-regexp or index exact name match).
• Regex (.*) — Interpret the query as a regular expression.

Sidebar Views

SI Search contributes two views to its own activity bar container:

Status Bar

The status bar item (bottom-left) shows the current index state:

How It Works

Symbol Parsing

SI Search loads tree-sitter WASM grammars for C and C++ at runtime. For each source file, it runs tree-sitter S-expression queries to extract symbol definitions:

;; Example: extract function names
(function_definition
  declarator: (function_declarator
    declarator: (identifier) @name)) @def

Each extracted symbol records: name, kind, file path, line number, column, and the line's text content.

Index Structure

The in-memory index uses two maps for different access patterns:

• symbolsByFile (Map<relativePath, SymbolEntry[]>) — Enables O(1) per-file removal during incremental updates.
• nameIndex (Map<lowerCaseName, SymbolEntry[]>) — Enables O(1) exact lookup and fast substring scanning.

Disk Persistence

The index is serialized to {workspaceRoot}/.sisearch/index.json as a JSON file containing:

{
  "version": 1,
  "createdAt": 1712700000000,
  "workspaceRoot": "/path/to/workspace",
  "files": [{ "relativePath": "...", "mtime": ..., "size": ..., "symbolCount": ... }],
  "symbols": [{ "name": "...", "kind": "function", "filePath": "...", ... }]
}

On VS Code startup, the index is loaded from disk. The version field ensures forward compatibility—if the format changes, old indexes are discarded and rebuilt.

Incremental Sync

During sync, SI Search compares each file's mtime and size against the stored metadata. Only files that are new, modified, or deleted are processed. This makes re-syncing a large codebase (e.g., Linux kernel) take seconds instead of minutes.

Requirements

• VS Code 1.85.0 or later.
• No external dependencies required. All tree-sitter WASM grammars and the ripgrep binary are bundled with the extension.

Build from Source

Prerequisites

• Node.js 18+ and npm
• VS Code 1.85.0+

Install Dependencies

npm install

Compile

npm run compile

This runs tsc -p ./ to compile TypeScript to out/.

Watch Mode (for development)

npm run watch

Package as VSIX

npx @vscode/vsce package

This will:

1. Copy WASM files from node_modules to wasm/ (npm run copy-wasm)
2. Compile TypeScript (npm run compile)
3. Package everything into sisearch-<version>.vsix

Install VSIX

code --install-extension sisearch-<version>.vsix

Or in VS Code: Ctrl+Shift+P → Extensions: Install from VSIX...

Known Limitations

• Symbol indexing currently supports C and C++ only. Other languages fall back to ripgrep full-text search.
• The hover preview renders code using the current VS Code theme via shiki. Some custom themes may not render perfectly.
• The .sisearch/ directory is created in the workspace root. Add it to your .gitignore if needed.

License

MIT