wasm-sandbox 0.4.1

//! WebAssembly Component Model implementation
//! 
//! This module provides support for the WebAssembly Component Model,
//! which enables more complex and type-safe interactions between host and guest.
//! 
//! The Component Model allows for:
//! - Interface-driven development
//! - Multi-language component authoring
//! - Structured data exchange
//! - Explicit imports and exports

use std::sync::Arc;
use std::path::Path;
use uuid::Uuid;

use wasmtime::component::{Component, Instance, Linker};
use wasmtime::{Engine, Store};

use crate::error::{Error, Result};
use crate::runtime::{WasmModule, WasmInstance, WasmRuntime, WasmFunctionCaller, WasmInstanceState, ModuleId, RuntimeConfig, RuntimeMetrics};
use crate::security::{Capabilities, ResourceLimits};

/// A WebAssembly Component Module
pub struct ComponentModule {
    /// Unique identifier for this module
    id: ModuleId,
    
    /// The compiled component
    component: Component,
    
    /// Component name if available
    name: Option<String>,
    
    /// Component metadata
    metadata: serde_json::Value,
}

impl ComponentModule {
    /// Create a new Component Module from WebAssembly bytes
    pub fn new(engine: &Engine, bytes: &[u8]) -> Result<Self> {
        let component = Component::new(engine, bytes)
            .map_err(|e| Error::ModuleLoad { message: e.to_string() })?;
            
        Ok(Self {
            id: ModuleId::new(),
            component,
            name: None,
            metadata: serde_json::Value::Null,
        })
    }
    
    /// Get the component
    pub fn component(&self) -> &Component {
        &self.component
    }
    
    /// Set component name
    pub fn with_name(mut self, name: impl Into<String>) -> Self {
        self.name = Some(name.into());
        self
    }
    
    /// Set component metadata
    pub fn with_metadata(mut self, metadata: serde_json::Value) -> Self {
        self.metadata = metadata;
        self
    }
}

impl WasmModule for ComponentModule {
    fn id(&self) -> ModuleId {
        self.id
    }
    
    fn name(&self) -> Option<&str> {
        self.name.as_deref()
    }
    
    fn size(&self) -> usize {
        // Components don't expose raw size easily, return 0 for now
        0
    }
    
    fn exports(&self) -> Vec<String> {
        // Component exports would need to be introspected
        // For now return empty vector
        Vec::new()
    }
    
    fn clone_module(&self) -> Box<dyn WasmModule> {
        Box::new(ComponentModule {
            id: self.id,
            component: self.component.clone(),
            name: self.name.clone(),
            metadata: self.metadata.clone(),
        })
    }
    
    fn as_any(&self) -> &dyn std::any::Any {
        self
    }
}

/// A WebAssembly Component Instance
pub struct ComponentInstance<T: 'static> {
    /// Unique identifier for this instance
    #[allow(dead_code)]
    id: Uuid,
    
    /// The module this instance was created from
    #[allow(dead_code)]
    module_id: Uuid,
    
    /// The wasmtime component instance
    instance: Instance,
    
    /// Store containing the instance
    store: Store<T>,
    
    /// Instance capabilities
    #[allow(dead_code)]
    capabilities: Capabilities,
    
    /// Resource limits
    #[allow(dead_code)]
    resource_limits: ResourceLimits,
}

impl<T: Send + 'static> ComponentInstance<T> {
    /// Create a new Component Instance
    pub fn new(
        module: &ComponentModule, 
        mut store: Store<T>,
        linker: &Linker<T>,
        capabilities: Capabilities,
        resource_limits: ResourceLimits
    ) -> Result<Self> {
        let instance = linker.instantiate(&mut store, &module.component)
            .map_err(|e| Error::InstanceCreation { reason: e.to_string(), instance_id: None })?;
            
        Ok(Self {
            id: Uuid::new_v4(),
            module_id: module.id.as_uuid(),
            instance,
            store,
            capabilities,
            resource_limits,
        })
    }
    
    /// Get a reference to the store
    pub fn store(&self) -> &Store<T> {
        &self.store
    }
    
    /// Get a mutable reference to the store
    pub fn store_mut(&mut self) -> &mut Store<T> {
        &mut self.store
    }
    
    /// Get a reference to the instance
    pub fn instance(&self) -> &Instance {
        &self.instance
    }
}

impl<T: Send + Sync + 'static> WasmInstance for ComponentInstance<T> {
    fn state(&self) -> WasmInstanceState {
        WasmInstanceState::Running // Components are always running if created
    }
    
    fn memory_usage(&self) -> usize {
        // Component memory usage would need specific wasmtime API calls
        0
    }
    
    fn fuel_usage(&self) -> Option<u64> {
        // Fuel tracking would need to be implemented in store config
        None
    }
    
    fn reset_fuel(&self) -> Result<()> {
        // Would need store.set_fuel() call
        Ok(())
    }
    
    fn add_fuel(&self, _fuel: u64) -> Result<()> {
        // Would need store.add_fuel() call
        Ok(())
    }
    
    unsafe fn memory_ptr(&self) -> Result<*mut u8> {
        // Direct memory access for components would be complex
        Err(Error::UnsupportedOperation { message: "Direct memory access not supported for components".to_string() })
    }
    
    fn memory_size(&self) -> usize {
        // Component memory size would need specific API
        0
    }
    
    fn function_caller(&self) -> Box<dyn WasmFunctionCaller> {
        Box::new(ComponentFunctionCaller {})
    }
    
    fn call_simple_function(&self, _function_name: &str, _params: &[i32]) -> Result<i32> {
        // Component function calling is different from core modules
        Err(Error::UnsupportedOperation { message: "Simple function calls not supported for components".to_string() })
    }
}

/// Function caller implementation for WebAssembly Components
pub struct ComponentFunctionCaller {}

impl WasmFunctionCaller for ComponentFunctionCaller {
    fn call_function_json(
        &self,
        _function_name: &str,
        _params_json: &str,
    ) -> Result<String> {
        Err(Error::UnsupportedOperation { message: "Component function calling not yet implemented".to_string() })
    }
    
    fn call_function_msgpack(
        &self,
        _function_name: &str,
        _params_msgpack: &[u8],
    ) -> Result<Vec<u8>> {
        Err(Error::UnsupportedOperation { message: "Component function calling not yet implemented".to_string() })
    }
    
    fn as_any(&self) -> &dyn std::any::Any {
        self
    }
}

/// Component Model runtime manager
pub struct ComponentRuntime {
    /// Wasmtime engine
    engine: Engine,
    
    /// Default capabilities for new instances
    #[allow(dead_code)]
    default_capabilities: Capabilities,
    
    /// Default resource limits for new instances
    #[allow(dead_code)]
    default_resource_limits: ResourceLimits,
}

impl ComponentRuntime {
    /// Create a new Component Model runtime
    pub fn new(
        default_capabilities: Capabilities,
        default_resource_limits: ResourceLimits,
    ) -> Result<Self> {
        let mut config = wasmtime::Config::new();
        
        // Configure for component model support
        config.wasm_component_model(true);
        
        // Apply other security settings
        if default_resource_limits.memory.max_memory_pages > 0 {
            config.max_wasm_stack(default_resource_limits.memory.max_memory_pages as usize * 65536);
        }
        
        let engine = Engine::new(&config)
            .map_err(|e| Error::RuntimeInitialization { message: e.to_string() })?;
            
        Ok(Self {
            engine,
            default_capabilities,
            default_resource_limits,
        })
    }
    
    /// Create a new component module from bytes
    pub fn create_component_module(&self, bytes: &[u8]) -> Result<ComponentModule> {
        ComponentModule::new(&self.engine, bytes)
    }
    
    /// Create a new component module from a file
    pub fn create_component_module_from_file(&self, path: impl AsRef<Path>) -> Result<ComponentModule> {
        let bytes = std::fs::read(path)
            .map_err(|e| Error::IoError { message: e.to_string() })?;
        self.create_component_module(&bytes)
    }
    
    /// Create a default store for components
    pub fn create_store<T>(&self, data: T) -> Store<T> {
        Store::new(&self.engine, data)
    }
    
    /// Create a default linker for components
    pub fn create_linker<T>(&self) -> Linker<T> {
        Linker::new(&self.engine)
    }
}

impl WasmRuntime for ComponentRuntime {
    fn initialize(&mut self, _config: RuntimeConfig) -> Result<()> {
        // Component runtime initialization would configure the engine
        Ok(())
    }
    
    fn load_module(&self, bytes: &[u8]) -> Result<Box<dyn WasmModule>> {
        let module = self.create_component_module(bytes)?;
        Ok(Box::new(module))
    }
    
    fn get_module(&self, _id: ModuleId) -> Result<Arc<dyn WasmModule>> {
        // Would need to store modules in a map to retrieve by ID
        Err(Error::UnsupportedOperation { message: "Module retrieval not implemented for components yet".to_string() })
    }
    
    fn get_module_ids(&self) -> Vec<ModuleId> {
        // Would return IDs from stored modules
        Vec::new()
    }
    
    fn create_instance(
        &self, 
        _module: &dyn WasmModule, 
        _resources: ResourceLimits,
        _capabilities: Capabilities,
    ) -> Result<Box<dyn WasmInstance>> {
        Err(Error::UnsupportedOperation { message: "Instance creation interface not implemented for components yet".to_string() })
    }
    
    fn get_metrics(&self) -> RuntimeMetrics {
        RuntimeMetrics {
            compiled_modules: 0,
            active_instances: 0,
            total_memory_usage: 0,
            peak_memory_usage: 0,
            fuel_consumption_rate: None,
            cache_hit_rate: None,
            last_compilation_time_ms: None,
        }
    }
    
    fn shutdown(&self) -> Result<()> {
        // Component runtime shutdown
        Ok(())
    }
}