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//===--- GlobalCompilationDatabase.h -----------------------------*- C++-*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "CompileCommands.h"
#include "support/Function.h"
#include "support/Path.h"
#include "support/ThreadsafeFS.h"
#include "clang/Tooling/ArgumentsAdjusters.h"
#include "clang/Tooling/CompilationDatabase.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/StringMap.h"
#include <memory>
#include <mutex>
#include <vector>
namespace clang {
namespace clangd {
class Logger;
struct ProjectInfo {
// The directory in which the compilation database was discovered.
// Empty if directory-based compilation database discovery was not used.
std::string SourceRoot;
/// Provides compilation arguments used for parsing C and C++ files.
class GlobalCompilationDatabase {
virtual ~GlobalCompilationDatabase() = default;
/// If there are any known-good commands for building this file, returns one.
virtual llvm::Optional<tooling::CompileCommand>
getCompileCommand(PathRef File) const = 0;
/// Finds the closest project to \p File.
virtual llvm::Optional<ProjectInfo> getProjectInfo(PathRef File) const {
return llvm::None;
/// Makes a guess at how to build a file.
/// The default implementation just runs clang on the file.
/// Clangd should treat the results as unreliable.
virtual tooling::CompileCommand getFallbackCommand(PathRef File) const;
/// If the CDB does any asynchronous work, wait for it to complete.
/// For use in tests.
virtual bool blockUntilIdle(Deadline D) const { return true; }
using CommandChanged = Event<std::vector<std::string>>;
/// The callback is notified when files may have new compile commands.
/// The argument is a list of full file paths.
CommandChanged::Subscription watch(CommandChanged::Listener L) const {
return OnCommandChanged.observe(std::move(L));
mutable CommandChanged OnCommandChanged;
// Helper class for implementing GlobalCompilationDatabases that wrap others.
class DelegatingCDB : public GlobalCompilationDatabase {
DelegatingCDB(const GlobalCompilationDatabase *Base);
DelegatingCDB(std::unique_ptr<GlobalCompilationDatabase> Base);
getCompileCommand(PathRef File) const override;
llvm::Optional<ProjectInfo> getProjectInfo(PathRef File) const override;
tooling::CompileCommand getFallbackCommand(PathRef File) const override;
bool blockUntilIdle(Deadline D) const override;
const GlobalCompilationDatabase *Base;
std::unique_ptr<GlobalCompilationDatabase> BaseOwner;
CommandChanged::Subscription BaseChanged;
/// Gets compile args from tooling::CompilationDatabases built for parent
/// directories.
class DirectoryBasedGlobalCompilationDatabase
: public GlobalCompilationDatabase {
struct Options {
Options(const ThreadsafeFS &TFS) : TFS(TFS) {}
const ThreadsafeFS &TFS;
// Frequency to check whether e.g. compile_commands.json has changed.
std::chrono::steady_clock::duration RevalidateAfter =
// Frequency to check whether e.g. compile_commands.json has been created.
// (This is more expensive to check frequently, as we check many locations).
std::chrono::steady_clock::duration RevalidateMissingAfter =
// Used to provide per-file configuration.
std::function<Context(llvm::StringRef)> ContextProvider;
// Only look for a compilation database in this one fixed directory.
// FIXME: fold this into config/context mechanism.
llvm::Optional<Path> CompileCommandsDir;
DirectoryBasedGlobalCompilationDatabase(const Options &Opts);
~DirectoryBasedGlobalCompilationDatabase() override;
/// Scans File's parents looking for compilation databases.
/// Any extra flags will be added.
/// Might trigger OnCommandChanged, if CDB wasn't broadcasted yet.
getCompileCommand(PathRef File) const override;
/// Returns the path to first directory containing a compilation database in
/// \p File's parents.
llvm::Optional<ProjectInfo> getProjectInfo(PathRef File) const override;
bool blockUntilIdle(Deadline Timeout) const override;
Options Opts;
class DirectoryCache;
// Keyed by possibly-case-folded directory path.
// We can hand out pointers as they're stable and entries are never removed.
mutable llvm::StringMap<DirectoryCache> DirCaches;
mutable std::mutex DirCachesMutex;
std::vector<DirectoryCache *>
getDirectoryCaches(llvm::ArrayRef<llvm::StringRef> Dirs) const;
struct CDBLookupRequest {
PathRef FileName;
// Whether this lookup should trigger discovery of the CDB found.
bool ShouldBroadcast = false;
// Cached results newer than this are considered fresh and not checked
// against disk.
std::chrono::steady_clock::time_point FreshTime;
std::chrono::steady_clock::time_point FreshTimeMissing;
struct CDBLookupResult {
std::shared_ptr<const tooling::CompilationDatabase> CDB;
ProjectInfo PI;
llvm::Optional<CDBLookupResult> lookupCDB(CDBLookupRequest Request) const;
class BroadcastThread;
std::unique_ptr<BroadcastThread> Broadcaster;
// Performs broadcast on governed files.
void broadcastCDB(CDBLookupResult Res) const;
// cache test calls lookupCDB directly to ensure valid/invalid times.
friend class DirectoryBasedGlobalCompilationDatabaseCacheTest;
/// Extracts system include search path from drivers matching QueryDriverGlobs
/// and adds them to the compile flags. Base may not be nullptr.
/// Returns Base when \p QueryDriverGlobs is empty.
getQueryDriverDatabase(llvm::ArrayRef<std::string> QueryDriverGlobs,
std::unique_ptr<GlobalCompilationDatabase> Base);
/// Wraps another compilation database, and supports overriding the commands
/// using an in-memory mapping.
class OverlayCDB : public DelegatingCDB {
// Base may be null, in which case no entries are inherited.
// FallbackFlags are added to the fallback compile command.
// Adjuster is applied to all commands, fallback or not.
OverlayCDB(const GlobalCompilationDatabase *Base,
std::vector<std::string> FallbackFlags = {},
tooling::ArgumentsAdjuster Adjuster = nullptr);
getCompileCommand(PathRef File) const override;
tooling::CompileCommand getFallbackCommand(PathRef File) const override;
/// Sets or clears the compilation command for a particular file.
setCompileCommand(PathRef File,
llvm::Optional<tooling::CompileCommand> CompilationCommand);
mutable std::mutex Mutex;
llvm::StringMap<tooling::CompileCommand> Commands; /* GUARDED_BY(Mut) */
tooling::ArgumentsAdjuster ArgsAdjuster;
std::vector<std::string> FallbackFlags;
} // namespace clangd
} // namespace clang