29 file cache (#33)

* enable file caching

* allow force regeneration to be configurable

* rename cache file to .typecache

* update caching info in readme

* add more test coverage

Author: thwbh

README.md

@@ -18,6 +18,7 @@ A command-line tool that automatically generates TypeScript bindings from your T
 - 🏷️ **Serde Support**: Respects `#[serde(rename)]` and `#[serde(rename_all)]` attributes
 - 🎯 **Type Safety**: Keeps frontend and backend types in sync
 - 🛠️ **Build Integration**: Works as standalone CLI or build dependency
+- ⚡ **Smart Caching**: Only regenerates when source files change
 
 ## Table of Contents
 
@@ -29,6 +30,8 @@ A command-line tool that automatically generates TypeScript bindings from your T
 - [TypeScript Compatibility](#typescript-compatibility)
 - [API Reference](#api-reference)
 - [Configuration](#configuration)
+- [Caching](#caching)
+- [Usage in CI](#usage-in-ci)
 - [Examples](#examples)
 - [Contributing](#contributing)
 
@@ -548,7 +551,8 @@ Options:
   -v, --validation <LIBRARY>    Validation library: zod or none [default: none]
       --verbose                 Verbose output
       --visualize-deps          Generate dependency graph
-  -c, --config <FILE>          Config file path
+  -c, --config <FILE>           Config file path
+  -f, --force                   Force regeneration, ignoring cache
 ```
 
 ```bash
@@ -619,11 +623,12 @@ In `tauri.conf.json`:
 ```json
 {
   "plugins": {
-    "tauri-typegen": {
-      "project_path": ".",
-      "output_path": "../src/generated",
-      "validation_library": "zod",
-      "verbose": true
+    "typegen": {
+      "projectPath": ".",
+      "outputPath": "../src/generated",
+      "validationLibrary": "zod",
+      "verbose": true,
+      "force": false
     }
   }
 }
@@ -692,6 +697,60 @@ export async function getFileInfo(): Promise<FileMetadata> {
 }
 ```
 
+## Caching
+
+Tauri-typegen uses smart caching to skip regeneration when nothing has changed, improving build times.
+
+### How It Works
+
+A `.typecache` file is created in your output directory containing hashes of:
+- All discovered Tauri commands
+- All discovered structs and enums
+- Configuration settings that affect output
+
+On subsequent runs, these hashes are compared. If nothing changed, generation is skipped.
+
+### Force Regeneration
+
+To bypass the cache and force regeneration:
+
+**CLI flag (highest priority):**
+```bash
+cargo tauri-typegen generate --force
+# or
+cargo tauri-typegen generate -f
+```
+
+**Config file (`tauri.conf.json`):**
+```json
+{
+  "plugins": {
+    "typegen": {
+      "force": true
+    }
+  }
+}
+```
+
+**Programmatic:**
+```rust
+let mut config = GenerateConfig::default();
+config.force = Some(true);
+```
+
+The CLI `--force` flag always overrides the config file value.
+
+### Cache File Location
+
+The cache file `.typecache` is stored in your output directory (e.g., `./src/generated/.typecache`). Add it to `.gitignore`:
+
+```gitignore
+# Tauri-typegen cache
+.typecache
+```
+
+Or if your entire output directory is gitignored, the cache file is already excluded.
+
 ## Usage in CI
 
 When running builds in CI/CD environments, you need to generate TypeScript bindings before the frontend build step.

src/bin/cargo-tauri-typegen.rs

@@ -2,6 +2,7 @@ use clap::Parser;
 use std::fs;
 use std::path::PathBuf;
 use tauri_typegen::analysis::CommandAnalyzer;
+use tauri_typegen::build::GenerationCache;
 use tauri_typegen::generators::create_generator;
 use tauri_typegen::interface::{
     print_dependency_visualization_info, print_usage_info, CargoCli, CargoSubcommands,
@@ -34,6 +35,7 @@ fn main() {
                     verbose,
                     visualize_deps,
                     config_file,
+                    force,
                 } => {
                     if let Err(e) = run_generate(
                         project_path,
@@ -42,6 +44,7 @@ fn main() {
                         verbose,
                         visualize_deps,
                         config_file,
+                        force,
                     ) {
                         eprintln!("Error: {}", e);
                         std::process::exit(1);
@@ -81,6 +84,7 @@ fn run_generate(
     verbose: bool,
     visualize_deps: bool,
     config_file: Option<PathBuf>,
+    force: bool,
 ) -> Result<(), Box<dyn std::error::Error>> {
     let logger = Logger::new(verbose, false);
     let mut reporter = ProgressReporter::new(logger, 4);
@@ -144,6 +148,10 @@ fn run_generate(
     if visualize_deps {
         config.visualize_deps = Some(true);
     }
+    // CLI --force flag overrides config
+    if force {
+        config.force = Some(true);
+    }
 
     reporter.complete_step(Some(&format!(
         "Using {} validation",
@@ -205,6 +213,35 @@ fn run_generate(
         return Ok(());
     }
 
+    // Check cache to see if regeneration is needed (unless force is set)
+    let discovered_structs = analyzer.get_discovered_structs();
+    let needs_regeneration = if config.should_force() {
+        if config.is_verbose() {
+            println!("🔄 Force flag set, regenerating bindings");
+        }
+        true
+    } else {
+        GenerationCache::needs_regeneration(
+            &config.output_path,
+            &commands,
+            discovered_structs,
+            &config,
+        )
+        .unwrap_or(true) // On error, assume regeneration is needed
+    };
+
+    if !needs_regeneration {
+        if config.is_verbose() {
+            println!("✨ Cache hit - no changes detected, skipping generation");
+        }
+        println!("✅ TypeScript bindings are up to date");
+        return Ok(());
+    }
+
+    if config.is_verbose() && !config.should_force() {
+        println!("🔄 Changes detected, regenerating bindings");
+    }
+
     // Generate bindings
     reporter.start_step("Generating TypeScript bindings");
     let validation = match config.validation_library.as_str() {
@@ -215,7 +252,7 @@ fn run_generate(
     let mut generator = create_generator(validation);
     let generated_files = generator.generate_models(
         &commands,
-        analyzer.get_discovered_structs(),
+        discovered_structs,
         &config.output_path,
         &analyzer,
         &config,
@@ -235,6 +272,12 @@ fn run_generate(
         print_dependency_visualization_info(&config.output_path);
     }
 
+    // Save cache after successful generation
+    let cache = GenerationCache::new(&commands, discovered_structs, &config)?;
+    if let Err(e) = cache.save(&config.output_path) {
+        eprintln!("Warning: Failed to save generation cache: {}", e);
+    }
+
     // Print summary
     reporter.finish("Generation complete");
     print_usage_info(&config.output_path, &generated_files, commands.len());
@@ -344,7 +387,8 @@ fn run_init(
         Some(config.validation_library.clone()),
         verbose,
         visualize_deps,
-        None, // No config file since we just created one
+        None,  // No config file since we just created one
+        false, // Respect cache behavior
     )?;
 
     logger.info("");