amberjs 1.17.0

// WASM 模块加载器
//
// 负责高效加载、验证和实例化 WebAssembly 模块

use anyhow::{Context, Result, anyhow};
use std::collections::{BTreeMap, HashMap};
use std::sync::{Arc, Mutex};

use wasmtime::{Config, Engine, Instance, Linker, Module, Store};
use std::time::{Duration, Instant};
use std::hash::Hasher;

/// WebAssembly 模块结构体
///
/// 封装已加载的 WASM 模块及其元数据
#[derive(Debug)]
pub struct WasmModule {
    /// 模块实例
    instance: Instance,
    /// 模块实例 ID
    id: String,
    /// 加载时间
    load_time: std::time::Duration,
    /// 模块大小（字节）
    size: usize,
}
impl PartialEq for WasmModule {
    fn eq(&self, other: &Self) -> bool {
        self.id == other.id
            && self.load_time == other.load_time
            && self.size == other.size
    }
}
impl WasmModule {
    /// 获取实例引用
    pub fn instance(&self) -> &Instance {
        &self.instance
    }
    /// 获取模块 ID
    pub fn id(&self) -> &str {
        &self.id
    }
    /// 获取加载时间
    pub fn load_time(&self) -> std::time::Duration {
        self.load_time
    }
    /// 获取模块大小
    pub fn size(&self) -> usize {
        self.size
    }
}
/// WASM 模块加载器
///
/// 提供高性能的 WASM 模块加载、验证和实例化功能
pub struct WasmModuleLoader {
    /// Wasmtime 引擎
    engine: Arc<Engine>,
    /// 加载器配置
    config: LoaderConfig,
}
#[derive(Debug, Clone)]
struct LoaderConfig {
    /// 最大模块大小（字节）
    max_module_size: usize,
    /// 是否启用验证
    enable_validation: bool,
    /// 是否启用并行加载
    enable_parallel: bool,
}
impl Default for LoaderConfig {
    fn default() -> Self {
        Self {
            max_module_size: 100 * 1024 * 1024, // 100MB
            enable_validation: true,
            enable_parallel: true,
        }
    }
}
impl WasmModuleLoader {
    /// 创建新的模块加载器
    ///
    /// # 返回值
    /// * `Result<WasmModuleLoader>` - 成功返回加载器，失败返回错误
    pub fn new() -> Result<Self> {
        let config: _ = Config::default();
        let engine: _ = Arc::new(Mutex::new(Engine::new(&config)))
            .context("Failed to create Wasmtime engine for module loader")?;
        Ok(WasmModuleLoader {
            engine,
            config: LoaderConfig::default(),
        })
    }
    /// 创建自定义配置的加载器
    ///
    /// # 参数
    /// * `max_module_size` - 最大模块大小
    /// * `enable_validation` - 是否启用验证
    /// * `enable_parallel` - 是否启用并行加载
    ///
    /// # 返回值
    /// * `Result<WasmModuleLoader>` - 加载器实例
    pub fn new_with_config(
        max_module_size: usize,
        enable_validation: bool,
        enable_parallel: bool,
    ) -> Result<Self> {
        let config: _ = Config::default();
        let engine: _ = Arc::new(Mutex::new(Engine::new(&config)))
            .context("Failed to create Wasmtime engine")?;
        Ok(WasmModuleLoader {
            engine,
            config: LoaderConfig {
                max_module_size,
                enable_validation,
                enable_parallel,
            },
        })
    }
    /// 加载 WebAssembly 模块
    ///
    /// # 参数
    /// * `wasm_bytes` - WASM 字节码
    ///
    /// # 返回值
    /// * `Result<WasmModule>` - 成功返回模块实例，失败返回错误
    ///
    /// # 示例
    /// ```
    /// let loader: _ = WasmModuleLoader::new()?;
    /// let wasm_bytes: _ = read_wasm_file("module.wasm")?;
    /// let module: _ = loader.load_module(&wasm_bytes)?;
    /// ```
    pub fn load_module(&self, wasm_bytes: &[u8]) -> Result<WasmModule> {
        let start: _ = Instant::now();
        // 检查模块大小
        if wasm_bytes.len() > self.config.max_module_size {
            return Err(anyhow!(
                "Module size {} exceeds maximum allowed size {}",
                wasm_bytes.len(),
                self.config.max_module_size
            ));
        }
        // 验证模块
        if self.config.enable_validation {
            Module::validate(&self.engine, wasm_bytes)
                .context("WASM module validation failed")?;
        }
        // 编译模块
        let module: _ = Module::new(&self.engine, wasm_bytes)
            .context("Failed to compile WASM module")?;
        // 创建存储（不使用 WASI，简化实现）
        let mut store: Store<()> = Store::new(&self.engine, ());
        // 创建链接器
        let linker: Linker<()> = Linker::new(&self.engine);
        // 实例化模块
        let instance: _ = linker
            .instantiate(&mut store, &module)
            .context("Failed to instantiate WASM module")?;
        // 生成模块 ID（基于内容哈希）
        let id: _ = self.generate_module_id(wasm_bytes)?;
        let load_time: _ = start.elapsed();
        let size: _ = wasm_bytes.len();
        Ok(WasmModule {
            instance,
            id,
            load_time,
            size,
        })
    }
    /// 从文件加载模块
    ///
    /// # 参数
    /// * `file_path` - 文件路径
    ///
    /// # 返回值
    /// * `Result<WasmModule>` - 模块实例
    pub fn load_module_from_file(&self, file_path: &str) -> Result<WasmModule> {
        let wasm_bytes: _ = std::fs::read(file_path)
            .context(format!("Failed to read WASM file: {}", file_path))?;
        self.load_module(&wasm_bytes)
    }
    /// 预热模块缓存
    ///
    /// # 参数
    /// * `wasm_bytes_list` - WASM 模块字节码列表
    ///
    /// # 返回值
    /// * `Result<Vec<WasmModule>` - 预热的模块列表
    pub fn prewarm_modules(&self, wasm_bytes_list: Vec<Vec<u8>>) -> Result<Vec<WasmModule>> {
        let mut modules = Vec::with_capacity(wasm_bytes_list.len());
        for wasm_bytes in wasm_bytes_list {
            let module: _ = self.load_module(&wasm_bytes)?;
            modules.push(module);
        }
        Ok(modules)
    }
    /// 获取引擎引用
    pub fn engine(&self) -> &Arc<Engine> {
        &self.engine
    }
    /// 生成模块 ID
    ///
    /// # 参数
    /// * `wasm_bytes` - WASM 字节码
    ///
    /// # 返回值
    /// * `Result<String>` - 模块 ID
    fn generate_module_id(&self, wasm_bytes: &[u8]) -> Result<String> {
        let mut hasher = Hasher::new();
        hasher.update(wasm_bytes);
        let hash: _ = hasher.finalize();
        Ok(hash.to_hex().to_string())
    }
    /// 获取加载器统计信息
    ///
    /// # 返回值
    /// * `LoaderStats` - 统计信息
    pub fn get_stats(&self) -> LoaderStats {
        LoaderStats {
            max_module_size: self.config.max_module_size,
            enable_validation: self.config.enable_validation,
            enable_parallel: self.config.enable_parallel,
            engine_info: format!("Wasmtime Engine v38.0"),
        }
    }
}
/// 模块加载器统计信息
#[derive(Debug, Clone)]
pub struct LoaderStats {
    /// 最大模块大小
    pub max_module_size: usize,
    /// 是否启用验证
    pub enable_validation: bool,
    /// 是否启用并行加载
    pub enable_parallel: bool,
    /// 引擎信息
    pub engine_info: String,
}
impl std::fmt::Display for LoaderStats {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f,
            "WasmModuleLoader Stats:\n\
             - Max Module Size: {} MB\n\
             - Validation: {}\n\
             - Parallel Loading: {}\n\
             - Engine: {}",
            self.max_module_size / (1024 * 1024),
            if self.enable_validation { "Enabled" } else { "Disabled" },
            if self.enable_parallel { "Enabled" } else { "Disabled" },
            self.engine_info
        )
    }
}
#[cfg(test)]
mod tests {
    #[test]
    fn test_loader_creation() {
        let loader: _ = WasmModuleLoader::new();
        assert!(loader.is_ok());
    }
    #[test]
    fn test_loader_with_config() {
        let loader: _ = WasmModuleLoader::new_with_config(
            50 * 1024 * 1024, // 50MB
            true,
            true,
        );
        assert!(loader.is_ok());
    }
    #[test]
    fn test_stats() {
        let loader: _ = WasmModuleLoader::new().unwrap();
        let stats: _ = loader.get_stats();
        assert!(stats.max_module_size > 0);
        assert!(stats.enable_validation);
    }
    /// 创建最小有效 WASM 模块的辅助函数
    fn create_minimal_wasm() -> Vec<u8> {
        // 最小有效 WASM 模块: 只有魔数和版本
        // 这是一个空模块，wasmtime 可以加载
        vec![
            0x00, 0x61, 0x73, 0x6d, // WASM 魔数
            0x01, 0x00, 0x00, 0x00, // WASM 版本 1
        ]
    }
}