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1//===--- ConfigProvider.h - Loading of user configuration --------*- C++-*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// Various clangd features have configurable behaviour (or can be disabled).10// The configuration system allows users to control this:11// - in a user config file, a project config file, via LSP, or via flags12// - specifying different settings for different files13// This file defines the structures used for this, that produce a Config.14//15//===----------------------------------------------------------------------===//16 17#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_CONFIGPROVIDER_H18#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_CONFIGPROVIDER_H19 20#include "llvm/ADT/StringRef.h"21#include "llvm/Support/SourceMgr.h"22#include <chrono>23#include <string>24#include <vector>25 26namespace clang {27namespace clangd {28struct Config;29class ThreadsafeFS;30namespace config {31 32/// Describes the context used to evaluate configuration fragments.33struct Params {34 /// Absolute path to a source file we're applying the config to. Unix slashes.35 /// Empty if not configuring a particular file.36 llvm::StringRef Path;37 /// Hint that stale data is OK to improve performance (e.g. avoid IO).38 /// FreshTime sets a bound for how old the data can be.39 /// By default, providers should validate caches against the data source.40 std::chrono::steady_clock::time_point FreshTime =41 std::chrono::steady_clock::time_point::max();42};43 44/// Used to report problems in parsing or interpreting a config.45/// Errors reflect structurally invalid config that should be user-visible.46/// Warnings reflect e.g. unknown properties that are recoverable.47/// Notes are used to report files and fragments.48/// (This can be used to track when previous warnings/errors have been "fixed").49using DiagnosticCallback = llvm::function_ref<void(const llvm::SMDiagnostic &)>;50 51/// A chunk of configuration that has been fully analyzed and is ready to apply.52/// Typically this is obtained from a Fragment by calling Fragment::compile().53///54/// Calling it updates the configuration to reflect settings from the fragment.55/// Returns true if the condition was met and the settings were used.56using CompiledFragment = std::function<bool(const Params &, Config &)>;57 58/// A source of configuration fragments.59/// Generally these providers reflect a fixed policy for obtaining config,60/// but return different concrete configuration over time.61/// e.g. a provider that reads config from files is responsive to file changes.62class Provider {63public:64 virtual ~Provider() = default;65 66 /// Reads fragments from a single YAML file with a fixed path. If non-empty,67 /// Directory will be used to resolve relative paths in the fragments.68 static std::unique_ptr<Provider> fromYAMLFile(llvm::StringRef AbsPath,69 llvm::StringRef Directory,70 const ThreadsafeFS &,71 bool Trusted = false);72 // Reads fragments from YAML files found relative to ancestors of Params.Path.73 //74 // All fragments that exist are returned, starting from distant ancestors.75 // For instance, given RelPath of ".clangd", then for source file /foo/bar.cc,76 // the searched fragments are [/.clangd, /foo/.clangd].77 //78 // If Params does not specify a path, no fragments are returned.79 static std::unique_ptr<Provider>80 fromAncestorRelativeYAMLFiles(llvm::StringRef RelPath, const ThreadsafeFS &,81 bool Trusted = false);82 83 /// A provider that includes fragments from all the supplied providers.84 /// Order is preserved; later providers take precedence over earlier ones.85 static std::unique_ptr<Provider> combine(std::vector<const Provider *>);86 87 /// Build a config based on this provider.88 Config getConfig(const Params &, DiagnosticCallback) const;89 90private:91 /// Provide fragments that may be relevant to the file.92 /// The configuration provider is not responsible for testing conditions.93 ///94 /// Providers are expected to cache compiled fragments, and only95 /// reparse/recompile when the source data has changed.96 /// Despite the need for caching, this function must be threadsafe.97 ///98 /// When parsing/compiling, the DiagnosticCallback is used to report errors.99 virtual std::vector<CompiledFragment>100 getFragments(const Params &, DiagnosticCallback) const = 0;101};102 103} // namespace config104} // namespace clangd105} // namespace clang106 107#endif108