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//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
/// \file This file implements the common abstractions for CAS database file.
///
//===----------------------------------------------------------------------===//
#include "DatabaseFile.h"
using namespace llvm;
using namespace llvm::cas;
using namespace llvm::cas::ondisk;
Error ondisk::createTableConfigError(std::errc ErrC, StringRef Path,
StringRef TableName, const Twine &Msg) {
return createStringError(make_error_code(ErrC),
Path + "[" + TableName + "]: " + Msg);
}
Error ondisk::checkTable(StringRef Label, size_t Expected, size_t Observed,
StringRef Path, StringRef TrieName) {
if (Expected == Observed)
return Error::success();
return createTableConfigError(std::errc::invalid_argument, Path, TrieName,
"mismatched " + Label +
" (expected: " + Twine(Expected) +
", observed: " + Twine(Observed) + ")");
}
Expected<DatabaseFile>
DatabaseFile::create(const Twine &Path, uint64_t Capacity,
function_ref<Error(DatabaseFile &)> NewDBConstructor) {
// Constructor for if the file doesn't exist.
auto NewFileConstructor = [&](MappedFileRegionArena &Alloc) -> Error {
if (Alloc.capacity() <
sizeof(Header) + sizeof(MappedFileRegionArena::Header))
return createTableConfigError(std::errc::argument_out_of_domain,
Path.str(), "datafile",
"Allocator too small for header");
(void)new (Alloc.data()) Header{getMagic(), getVersion(), {0}};
DatabaseFile DB(Alloc);
return NewDBConstructor(DB);
};
// Get or create the file.
MappedFileRegionArena Alloc;
if (Error E = MappedFileRegionArena::create(Path, Capacity, sizeof(Header),
NewFileConstructor)
.moveInto(Alloc))
return std::move(E);
return DatabaseFile::get(
std::make_unique<MappedFileRegionArena>(std::move(Alloc)));
}
Error DatabaseFile::addTable(TableHandle Table) {
assert(Table);
assert(&Table.getRegion() == &getRegion());
int64_t ExistingRootOffset = 0;
const int64_t NewOffset =
reinterpret_cast<const char *>(&Table.getHeader()) - getRegion().data();
if (H->RootTableOffset.compare_exchange_strong(ExistingRootOffset, NewOffset))
return Error::success();
// Silently ignore attempts to set the root to itself.
if (ExistingRootOffset == NewOffset)
return Error::success();
// Return an proper error message.
TableHandle Root(getRegion(), ExistingRootOffset);
if (Root.getName() == Table.getName())
return createStringError(
make_error_code(std::errc::not_supported),
"collision with existing table of the same name '" + Table.getName() +
"'");
return createStringError(make_error_code(std::errc::not_supported),
"cannot add new table '" + Table.getName() +
"'"
" to existing root '" +
Root.getName() + "'");
}
std::optional<TableHandle> DatabaseFile::findTable(StringRef Name) {
int64_t RootTableOffset = H->RootTableOffset.load();
if (!RootTableOffset)
return std::nullopt;
TableHandle Root(getRegion(), RootTableOffset);
if (Root.getName() == Name)
return Root;
return std::nullopt;
}
Error DatabaseFile::validate(MappedFileRegion &Region) {
if (Region.size() < sizeof(Header))
return createStringError(std::errc::invalid_argument,
"database: missing header");
// Check the magic and version.
auto *H = reinterpret_cast<Header *>(Region.data());
if (H->Magic != getMagic())
return createStringError(std::errc::invalid_argument,
"database: bad magic");
if (H->Version != getVersion())
return createStringError(std::errc::invalid_argument,
"database: wrong version");
auto *MFH = reinterpret_cast<MappedFileRegionArena::Header *>(Region.data() +
sizeof(Header));
// Check the bump-ptr, which should point past the header.
if (MFH->BumpPtr.load() < (int64_t)sizeof(Header))
return createStringError(std::errc::invalid_argument,
"database: corrupt bump-ptr");
return Error::success();
}
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