Base class for threadsafe cache of data read from a file on disk. More...
#include <FileCache.h>
Protected Member Functions | |
| FileCache (PathRef Path) | |
| void | read (const ThreadsafeFS &TFS, std::chrono::steady_clock::time_point FreshTime, llvm::function_ref< void(std::optional< llvm::StringRef >)> Parse, llvm::function_ref< void()> Read) const |
| PathRef | path () const |
Detailed Description
Base class for threadsafe cache of data read from a file on disk.
We want configuration files to be "live" as much as possible. Reading them every time is simplest, but caching solves a few problems:
- reading and parsing is cheap but not free (and happens on hot paths)
- we can ignore invalid data and use the old value (we may see truncated compile_commands.json from non-atomic writers)
- we avoid reporting the same errors repeatedly
We still read and parse the data synchronously on demand, but skip as much work as possible:
- if not enough wall-time has elapsed, assume the data is still up-to-date
- if we stat the file and it has the same mtime + size, don't read it
- obviously we only have to parse when we re-read the file (Tracking OS change events is an alternative, but difficult to do portably.)
Caches for particular data (e.g. compilation databases) should inherit and:
- add mutable storage for the cached parsed data
- add a public interface implemented on top of read()
Definition at line 40 of file FileCache.h.
Constructor & Destructor Documentation
◆ FileCache()
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protected |
Definition at line 25 of file FileCache.cpp.
Member Function Documentation
◆ path()
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inlineprotected |
Definition at line 63 of file FileCache.h.
Referenced by clang::clangd::config::FileConfigCache::get().
◆ read()
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protected |
Definition at line 31 of file FileCache.cpp.
References clang::clangd::CacheDiskMismatch, clang::clangd::FileNotFound, and clang::clangd::Read.
Referenced by clang::clangd::config::FileConfigCache::get().
The documentation for this class was generated from the following files:
