/// <summary>
/// Loads a transformed JavaScript file from the disk cache. If the cache is invalid or there is
/// no cached version, returns <c>null</c>.
/// </summary>
/// <param name="filename">Name of the file to load</param>
/// /// <param name="hash">Hash of the input file, to validate the cache</param>
/// <param name="forceGenerateSourceMap">
/// <c>true</c> to re-transform the file if a cached version with no source map is available
/// </param>
/// <returns></returns>
protected virtual JavaScriptWithSourceMap LoadFromFileCache(string filename, string hash, bool forceGenerateSourceMap)
{
var cacheFilename = GetOutputPath(filename);
if (!_fileSystem.FileExists(cacheFilename))
{
// Cache file doesn't exist on disk
return(null);
}
var cacheContents = _fileSystem.ReadAsString(cacheFilename);
if (!_fileCacheHash.ValidateHash(cacheContents, hash))
{
// Hash of the cache is invalid (file changed since the time the cache was written).
return(null);
}
// Cache is valid :D
// See if we have a source map cached alongside the file
SourceMap sourceMap = null;
var sourceMapFilename = GetSourceMapOutputPath(filename);
if (_fileSystem.FileExists(sourceMapFilename))
{
try
{
var sourceMapString = _fileSystem.ReadAsString(sourceMapFilename);
if (!string.IsNullOrEmpty(sourceMapString))
{
sourceMap = SourceMap.FromJson(sourceMapString);
}
}
catch (Exception e)
{
// Just ignore it
Trace.WriteLine("Error reading source map file: " + e.Message);
}
}
// If forceGenerateSourceMap is true, we need to explicitly ignore this cached version
// if there's no source map
if (forceGenerateSourceMap && sourceMap == null)
{
return(null);
}
return(new JavaScriptWithSourceMap
{
Code = cacheContents,
SourceMap = sourceMap,
Hash = hash,
});
}
/// <summary>
/// Transforms a JSX file. Results of the JSX to JavaScript transformation are cached.
/// </summary>
/// <param name="filename">Name of the file to load</param>
/// <param name="useHarmony"><c>true</c> if support for es6 syntax should be rewritten.</param>
/// <returns>JavaScript</returns>
public string TransformJsxFile(string filename, bool?useHarmony = null)
{
var fullPath = _fileSystem.MapPath(filename);
// 1. Check in-memory cache
return(_cache.GetOrInsert(
key: string.Format(JSX_CACHE_KEY, filename),
slidingExpiration: TimeSpan.FromMinutes(30),
cacheDependencyFiles: new[] { fullPath },
getData: () =>
{
// 2. Check on-disk cache
var contents = _fileSystem.ReadAsString(filename);
var hash = _fileCacheHash.CalculateHash(contents);
var cacheFilename = GetJsxOutputPath(filename);
if (_fileSystem.FileExists(cacheFilename))
{
var cacheContents = _fileSystem.ReadAsString(cacheFilename);
if (_fileCacheHash.ValidateHash(cacheContents, hash))
{
// Cache is valid :D
return cacheContents;
}
}
// 3. Not cached, perform the transformation
return TransformJsxWithHeader(contents, hash, useHarmony);
}
));
}
