package wazero

import (
	
	
	
	
	
	
	goruntime 
	

	
	
	
	
)

// CompilationCache reduces time spent compiling (Runtime.CompileModule) the same wasm module.
//
// # Notes
//
//   - This is an interface for decoupling, not third-party implementations.
//     All implementations are in wazero.
//   - Instances of this can be reused across multiple runtimes, if configured
//     via RuntimeConfig.
//   - The cache check happens before the compilation, so if multiple Goroutines are
//     trying to compile the same module simultaneously, it is possible that they
//     all compile the module. The design here is that the lock isn't held for the action "Compile"
//     but only for checking and saving the compiled result. Therefore, we strongly recommend that the embedder
//     does the centralized compilation in a single Goroutines (or multiple Goroutines per Wasm binary) to generate cache rather than
//     trying to Compile in parallel for a single module. In other words, we always recommend to produce CompiledModule
//     share it across multiple Goroutines to avoid trying to compile the same module simultaneously.
type CompilationCache interface{ api.Closer }

// NewCompilationCache returns a new CompilationCache to be passed to RuntimeConfig.
// This configures only in-memory cache, and doesn't persist to the file system. See wazero.NewCompilationCacheWithDir for detail.
//
// The returned CompilationCache can be used to share the in-memory compilation results across multiple instances of wazero.Runtime.
func () CompilationCache {
	return &cache{}
}

// NewCompilationCacheWithDir is like wazero.NewCompilationCache except the result also writes
// state into the directory specified by `dirname` parameter.
//
// If the dirname doesn't exist, this creates it or returns an error.
//
// Those running wazero as a CLI or frequently restarting a process using the same wasm should
// use this feature to reduce time waiting to compile the same module a second time.
//
// The contents written into dirname are wazero-version specific, meaning different versions of
// wazero will duplicate entries for the same input wasm.
//
// Note: The embedder must safeguard this directory from external changes.
func ( string) (CompilationCache, error) {
	 := &cache{}
	 := .ensuresFileCache(, version.GetWazeroVersion())
	return , 
}

// cache implements Cache interface.
type cache struct {
	// eng is the engine for this cache. If the cache is configured, the engine is shared across multiple instances of
	// Runtime, and its lifetime is not bound to them. Instead, the engine is alive until Cache.Close is called.
	engs      [engineKindCount]wasm.Engine
	fileCache filecache.Cache
	initOnces [engineKindCount]sync.Once
}

func ( *cache) ( engineKind,  newEngine,  context.Context,  api.CoreFeatures) wasm.Engine {
	.initOnces[].Do(func() { .engs[] = (, , .fileCache) })
	return .engs[]
}

// Close implements the same method on the Cache interface.
func ( *cache) ( context.Context) ( error) {
	for ,  := range .engs {
		if  != nil {
			if  = .Close();  != nil {
				return
			}
		}
	}
	return
}

func ( *cache) ( string,  string) error {
	// Resolve a potentially relative directory into an absolute one.
	var  error
	,  = filepath.Abs()
	if  != nil {
		return 
	}

	// Ensure the user-supplied directory.
	if  = mkdir();  != nil {
		return 
	}

	// Create a version-specific directory to avoid conflicts.
	 := path.Join(, "wazero-"++"-"+goruntime.GOARCH+"-"+goruntime.GOOS)
	if  = mkdir();  != nil {
		return 
	}

	.fileCache = filecache.New()
	return nil
}

func mkdir( string) error {
	if ,  := os.Stat(); errors.Is(, os.ErrNotExist) {
		// If the directory not found, create the cache dir.
		if  = os.MkdirAll(, 0o700);  != nil {
			return fmt.Errorf("create directory %s: %v", , )
		}
	} else if  != nil {
		return 
	} else if !.IsDir() {
		return fmt.Errorf("%s is not dir", )
	}
	return nil
}