2936a2c882
Add OnDiskTrieRawHashMap. This is a on-disk persistent hash map that uses a Trie data structure that is similar to TrieRawHashMap. OnDiskTrieRawHashMap is thread safe and process safe. It is mostly lock free, except it internally coordinates cross process creation and closing using file lock.
124 lines
4.8 KiB
C++
124 lines
4.8 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file This file implements the common abstractions for CAS database file.
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///
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//===----------------------------------------------------------------------===//
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#include "DatabaseFile.h"
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using namespace llvm;
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using namespace llvm::cas;
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using namespace llvm::cas::ondisk;
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Error ondisk::createTableConfigError(std::errc ErrC, StringRef Path,
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StringRef TableName, const Twine &Msg) {
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return createStringError(make_error_code(ErrC),
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Path + "[" + TableName + "]: " + Msg);
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}
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Error ondisk::checkTable(StringRef Label, size_t Expected, size_t Observed,
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StringRef Path, StringRef TrieName) {
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if (Expected == Observed)
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return Error::success();
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return createTableConfigError(std::errc::invalid_argument, Path, TrieName,
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"mismatched " + Label +
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" (expected: " + Twine(Expected) +
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", observed: " + Twine(Observed) + ")");
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}
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Expected<DatabaseFile>
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DatabaseFile::create(const Twine &Path, uint64_t Capacity,
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function_ref<Error(DatabaseFile &)> NewDBConstructor) {
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// Constructor for if the file doesn't exist.
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auto NewFileConstructor = [&](MappedFileRegionArena &Alloc) -> Error {
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if (Alloc.capacity() <
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sizeof(Header) + sizeof(MappedFileRegionArena::Header))
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return createTableConfigError(std::errc::argument_out_of_domain,
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Path.str(), "datafile",
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"Allocator too small for header");
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(void)new (Alloc.data()) Header{getMagic(), getVersion(), {0}};
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DatabaseFile DB(Alloc);
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return NewDBConstructor(DB);
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};
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// Get or create the file.
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MappedFileRegionArena Alloc;
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if (Error E = MappedFileRegionArena::create(Path, Capacity, sizeof(Header),
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NewFileConstructor)
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.moveInto(Alloc))
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return std::move(E);
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return DatabaseFile::get(
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std::make_unique<MappedFileRegionArena>(std::move(Alloc)));
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}
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Error DatabaseFile::addTable(TableHandle Table) {
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assert(Table);
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assert(&Table.getRegion() == &getRegion());
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int64_t ExistingRootOffset = 0;
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const int64_t NewOffset =
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reinterpret_cast<const char *>(&Table.getHeader()) - getRegion().data();
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if (H->RootTableOffset.compare_exchange_strong(ExistingRootOffset, NewOffset))
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return Error::success();
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// Silently ignore attempts to set the root to itself.
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if (ExistingRootOffset == NewOffset)
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return Error::success();
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// Return an proper error message.
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TableHandle Root(getRegion(), ExistingRootOffset);
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if (Root.getName() == Table.getName())
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return createStringError(
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make_error_code(std::errc::not_supported),
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"collision with existing table of the same name '" + Table.getName() +
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"'");
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return createStringError(make_error_code(std::errc::not_supported),
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"cannot add new table '" + Table.getName() +
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"'"
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" to existing root '" +
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Root.getName() + "'");
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}
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std::optional<TableHandle> DatabaseFile::findTable(StringRef Name) {
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int64_t RootTableOffset = H->RootTableOffset.load();
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if (!RootTableOffset)
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return std::nullopt;
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TableHandle Root(getRegion(), RootTableOffset);
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if (Root.getName() == Name)
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return Root;
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return std::nullopt;
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}
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Error DatabaseFile::validate(MappedFileRegion &Region) {
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if (Region.size() < sizeof(Header))
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return createStringError(std::errc::invalid_argument,
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"database: missing header");
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// Check the magic and version.
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auto *H = reinterpret_cast<Header *>(Region.data());
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if (H->Magic != getMagic())
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return createStringError(std::errc::invalid_argument,
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"database: bad magic");
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if (H->Version != getVersion())
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return createStringError(std::errc::invalid_argument,
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"database: wrong version");
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auto *MFH = reinterpret_cast<MappedFileRegionArena::Header *>(Region.data() +
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sizeof(Header));
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// Check the bump-ptr, which should point past the header.
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if (MFH->BumpPtr.load() < (int64_t)sizeof(Header))
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return createStringError(std::errc::invalid_argument,
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"database: corrupt bump-ptr");
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return Error::success();
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}
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