llvm/llvm/include/llvm/Support/CachePruning.h

//=- CachePruning.h - Helper to manage the pruning of a cache dir -*- C++ -*-=//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements pruning of a directory intended for cache storage, using
// various policies.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_SUPPORT_CACHEPRUNING_H
#define LLVM_SUPPORT_CACHEPRUNING_H

#include "llvm/Support/MemoryBuffer.h"
#include <chrono>
#include <optional>

namespace llvm {

template <typename T> class Expected;
class StringRef;

/// Policy for the pruneCache() function. A default constructed
/// CachePruningPolicy provides a reasonable default policy.
struct CachePruningPolicy { … };

/// Parse the given string as a cache pruning policy. Defaults are taken from a
/// default constructed CachePruningPolicy object.
/// For example: "prune_interval=30s:prune_after=24h:cache_size=50%"
/// which means a pruning interval of 30 seconds, expiration time of 24 hours
/// and maximum cache size of 50% of available disk space.
Expected<CachePruningPolicy> parseCachePruningPolicy(StringRef PolicyStr);

/// Peform pruning using the supplied policy, returns true if pruning
/// occurred, i.e. if Policy.Interval was expired.
///
/// Check whether cache pruning happens using the supplied policy, adds a
/// ThinLTO warning if cache_size_bytes or cache_size_files is too small for the
/// current link job. The warning recommends the user to consider adjusting
/// --thinlto-cache-policy.
///
/// As a safeguard against data loss if the user specifies the wrong directory
/// as their cache directory, this function will ignore files not matching the
/// pattern "llvmcache-*".
bool pruneCache(StringRef Path, CachePruningPolicy Policy,
                const std::vector<std::unique_ptr<MemoryBuffer>> &Files = {});
} // namespace llvm

#endif