public async Task IncrementalBuild()

in src/Analysis/Codelyzer.Analysis.Build/ProjectBuildHandler.cs [436:477]
34 lines of code
3 McCabe index (conditional complexity)

        public async Task<ProjectBuildResult> IncrementalBuild(string filePath, ProjectBuildResult projectBuildResult)
        {
            await Task.Run(() =>
            {
                var languageVersion = LanguageVersion.Default;
                if (projectBuildResult.Compilation is CSharpCompilation compilation)
                {
                    languageVersion = compilation.LanguageVersion;
                }

                var fileContents = File.ReadAllText(filePath);
                var updatedTree = CSharpSyntaxTree.ParseText(SourceText.From(fileContents), path: filePath, options: new CSharpParseOptions(languageVersion));

                var syntaxTree = Compilation.SyntaxTrees.FirstOrDefault(syntaxTree => syntaxTree.FilePath == filePath);
                var preportSyntaxTree = Compilation.SyntaxTrees.FirstOrDefault(syntaxTree => syntaxTree.FilePath == filePath);

                Compilation = Compilation.RemoveSyntaxTrees(syntaxTree).AddSyntaxTrees(updatedTree);
                PrePortCompilation = PrePortCompilation?.RemoveSyntaxTrees(preportSyntaxTree).AddSyntaxTrees(updatedTree);

                var oldSourceFileBuildResult = projectBuildResult.SourceFileBuildResults.FirstOrDefault(sourceFile => sourceFile.SourceFileFullPath == filePath);
                projectBuildResult.SourceFileBuildResults.Remove(oldSourceFileBuildResult);

                var sourceFilePath = Path.GetRelativePath(projectBuildResult.ProjectRootPath, filePath);
                var preportTree = PrePortCompilation?.SyntaxTrees?.FirstOrDefault(s => s.FilePath == syntaxTree.FilePath);
                var fileResult = new SourceFileBuildResult
                {
                    SyntaxTree = updatedTree,
                    PrePortSemanticModel = preportTree != null ? PrePortCompilation?.GetSemanticModel(preportTree) : null,
                    SemanticModel = Compilation.GetSemanticModel(updatedTree),
                    SourceFileFullPath = syntaxTree.FilePath,
                    SyntaxGenerator = SyntaxGenerator.GetGenerator(Project),
                    SourceFilePath = sourceFilePath
                };

                projectBuildResult.SourceFileBuildResults.Add(fileResult);
                projectBuildResult.Compilation = Compilation;
                projectBuildResult.PrePortCompilation = PrePortCompilation;
            });


            return projectBuildResult;
        }