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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System;
using System.Collections.Concurrent;
using System.Composition;
using System.IO;
using Microsoft.CodeAnalysis.ErrorReporting;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.Snippets;
using Microsoft.CommonLanguageServerProtocol.Framework;
using Roslyn.Utilities;
namespace Microsoft.CodeAnalysis.LanguageServer.Handler.InlineCompletions;
/// <summary>
/// Server instance agnostic snippet parser and cache.
/// This can be re-used across LSP servers as we're just storing an
/// internal representation of an XML snippet.
/// </summary>
[Export(typeof(XmlSnippetParser)), Shared]
internal partial class XmlSnippetParser
{
/// <summary>
/// Cache to hold onto the parsed XML for a particular snippet.
/// </summary>
private readonly ConcurrentDictionary<string, ParsedXmlSnippet?> _parsedSnippetsCache = [];
[ImportingConstructor]
[Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
public XmlSnippetParser()
{
}
internal ParsedXmlSnippet? GetParsedXmlSnippet(SnippetInfo matchingSnippetInfo, ILspLogger logger)
{
if (_parsedSnippetsCache.TryGetValue(matchingSnippetInfo.Title, out var cachedSnippet))
{
if (cachedSnippet == null)
{
logger.LogWarning($"Returning a null cached snippet for {matchingSnippetInfo.Title}");
}
return cachedSnippet;
}
ParsedXmlSnippet? parsedSnippet = null;
try
{
logger.LogInformation($"Reading snippet for {matchingSnippetInfo.Title} with path {matchingSnippetInfo.Path}");
parsedSnippet = GetAndParseSnippetFromFile(matchingSnippetInfo);
}
catch (Exception ex) when (FatalError.ReportAndCatch(ex, ErrorSeverity.General))
{
logger.LogError($"Got exception parsing xml snippet {matchingSnippetInfo.Title} from file {matchingSnippetInfo.Path}");
logger.LogException(ex);
}
// Add the snippet to the cache regardless of if we succeeded in parsing it.
// We're not likely to succeed in parsing on a second try if we failed initially, so we cache it to avoid repeatedly failing.
_parsedSnippetsCache.TryAdd(matchingSnippetInfo.Title, parsedSnippet);
return parsedSnippet;
}
private static ParsedXmlSnippet GetAndParseSnippetFromFile(SnippetInfo snippetInfo)
{
// Read the XML file to get the snippet and snippet metadata.
var matchingSnippet = RetrieveSnippetXmlFromFile(snippetInfo);
Contract.ThrowIfFalse(matchingSnippet.IsExpansionSnippet(), "Only expansion snippets are supported");
if (!matchingSnippet.IsExpansionSnippet())
{
throw new InvalidOperationException();
}
var expansion = new ExpansionTemplate(matchingSnippet);
// Parse the snippet XML into snippet parts we can cache.
var parsedSnippet = expansion.Parse();
return parsedSnippet;
}
private static CodeSnippet RetrieveSnippetXmlFromFile(SnippetInfo snippetInfo)
{
var path = snippetInfo.Path;
if (path == null)
{
throw new ArgumentException($"Missing file path for snippet {snippetInfo.Title}");
}
if (!File.Exists(path))
{
throw new InvalidOperationException($"Snippet {snippetInfo.Title} has an invalid file path: {snippetInfo.Path}");
}
// Load the xml for the snippet from disk.
// Any exceptions thrown here we allow to bubble up and let the queue log it.
var snippet = CodeSnippet.ReadSnippetFromFile(snippetInfo.Path, snippetInfo.Title);
return snippet;
}
internal TestAccessor GetTestAccessor() => new TestAccessor(this);
internal readonly struct TestAccessor
{
private readonly XmlSnippetParser _snippetParser;
public TestAccessor(XmlSnippetParser snippetParser)
{
_snippetParser = snippetParser;
}
public int GetCachedSnippetsCount() => _snippetParser._parsedSnippetsCache.Count;
public ParsedXmlSnippet GetCachedSnippet(string snippet) => _snippetParser._parsedSnippetsCache[snippet]!;
}
}
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