1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
|
// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_VALUE_STORE_LAZY_LEVELDB_H_
#define COMPONENTS_VALUE_STORE_LAZY_LEVELDB_H_
#include <memory>
#include <optional>
#include <string>
#include "base/files/file_path.h"
#include "base/memory/raw_ptr.h"
#include "base/metrics/histogram_base.h"
#include "base/values.h"
#include "components/value_store/value_store.h"
#include "third_party/leveldatabase/env_chromium.h"
#include "third_party/leveldatabase/src/include/leveldb/db.h"
namespace leveldb {
class Iterator;
} // namespace leveldb
namespace value_store {
// Manages a lazy connection to a leveldb database. "lazy" means that the
// leveldb database will be opened, when necessary, when any *public* method is
// called. Derived classes are responsible for calling EnsureDbIsOpen() before
// calling any other *protected* method.
class LazyLevelDb {
public:
LazyLevelDb(const LazyLevelDb&) = delete;
LazyLevelDb& operator=(const LazyLevelDb&) = delete;
// Creates a new database iterator. This iterator *must* be deleted before
// this database is closed.
ValueStore::Status CreateIterator(
const leveldb::ReadOptions& read_options,
std::unique_ptr<leveldb::Iterator>* iterator);
// Converts a leveldb::Status to a ValueStore::Status. Will also sanitize path
// to eliminate user data path.
ValueStore::Status ToValueStoreError(const leveldb::Status& status);
// Deletes a value (identified by |key|) from the database.
ValueStore::Status Delete(const std::string& key);
protected:
LazyLevelDb(const std::string& uma_client_name, const base::FilePath& path);
~LazyLevelDb();
// Closes, if necessary, and deletes the database directory.
bool DeleteDbFile();
// Fixes the |key| or database. If |key| is not null and the database is open
// then the key will be deleted. Otherwise the database will be repaired, and
// failing that will be deleted.
ValueStore::BackingStoreRestoreStatus FixCorruption(const std::string* key);
// Reads a |key| from the database, and populates |value| with the result. If
// the specified value does not exist in the database then an "OK" status will
// be returned and value will be unchanged. Caller must ensure the database is
// open before calling this method.
ValueStore::Status Read(const std::string& key,
std::optional<base::Value>* value);
// Opens the underlying database if not yet open. If the open fails due to
// corruption will attempt to repair the database. Failing that, will attempt
// to delete the database. Will only attempt a single recovery.
ValueStore::Status EnsureDbIsOpen();
std::string_view open_histogram_name() const {
return open_histogram_->histogram_name();
}
leveldb::DB* db() { return db_.get(); }
const leveldb::ReadOptions& read_options() const { return read_options_; }
const leveldb::WriteOptions& write_options() const { return write_options_; }
private:
// The leveldb to which this class reads/writes.
std::unique_ptr<leveldb::DB> db_;
// The path to the underlying leveldb.
const base::FilePath db_path_;
// The options to be used when this database is lazily opened.
leveldb_env::Options open_options_;
// The options to be used for all database read operations.
leveldb::ReadOptions read_options_;
// The options to be used for all database write operations.
leveldb::WriteOptions write_options_;
// Set when this database has tried to repair (and failed) to prevent
// unbounded attempts to open a bad/unrecoverable database.
bool db_unrecoverable_ = false;
// Used for UMA logging.
raw_ptr<base::HistogramBase> open_histogram_ = nullptr;
};
} // namespace value_store
#endif // COMPONENTS_VALUE_STORE_LAZY_LEVELDB_H_
|
