Clean up extension confirmation prompts and make them consistent between Views and...
[chromium-blink-merge.git] / components / metrics / persisted_logs.h
blob1fb99c696df0be2ff9e72c05bc38eed8c7a99b4f
1 // Copyright 2014 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef COMPONENTS_METRICS_PERSISTED_LOGS_H_
6 #define COMPONENTS_METRICS_PERSISTED_LOGS_H_
8 #include <string>
9 #include <vector>
11 #include "base/basictypes.h"
12 #include "base/logging.h"
13 #include "base/values.h"
15 class PrefService;
17 namespace metrics {
19 // Maintains a list of unsent logs that are written and restored from disk.
20 class PersistedLogs {
21 public:
22 // Used to produce a histogram that keeps track of the status of recalling
23 // persisted per logs.
24 enum LogReadStatus {
25 RECALL_SUCCESS, // We were able to correctly recall a persisted log.
26 LIST_EMPTY, // Attempting to recall from an empty list.
27 LIST_SIZE_MISSING, // Failed to recover list size using GetAsInteger().
28 LIST_SIZE_TOO_SMALL, // Too few elements in the list (less than 3).
29 LIST_SIZE_CORRUPTION, // List size is not as expected.
30 LOG_STRING_CORRUPTION, // Failed to recover log string using GetAsString().
31 CHECKSUM_CORRUPTION, // Failed to verify checksum.
32 CHECKSUM_STRING_CORRUPTION, // Failed to recover checksum string using
33 // GetAsString().
34 DECODE_FAIL, // Failed to decode log.
35 DEPRECATED_XML_PROTO_MISMATCH, // The XML and protobuf logs have
36 // inconsistent data.
37 END_RECALL_STATUS // Number of bins to use to create the histogram.
40 // Constructs a PersistedLogs that stores data in |local_state| under the
41 // preference |pref_name|.
42 // Calling code is responsible for ensuring that the lifetime of |local_state|
43 // is longer than the lifetime of PersistedLogs.
45 // When saving logs to disk, stores either the first |min_log_count| logs, or
46 // at least |min_log_bytes| bytes of logs, whichever is greater.
48 // If the optional |max_log_size| parameter is non-zero, all logs larger than
49 // that limit will be skipped when writing to disk.
50 PersistedLogs(PrefService* local_state,
51 const char* pref_name,
52 size_t min_log_count,
53 size_t min_log_bytes,
54 size_t max_log_size);
55 ~PersistedLogs();
57 // Write list to storage.
58 void SerializeLogs() const;
60 // Reads the list from the preference.
61 LogReadStatus DeserializeLogs();
63 // Adds a log to the list.
64 void StoreLog(const std::string& log_data);
66 // Stages the most recent log. The staged_log will remain the same even if
67 // additional logs are added.
68 void StageLog();
70 // Remove the staged log.
71 void DiscardStagedLog();
73 // True if a log has been staged.
74 bool has_staged_log() const { return staged_log_index_ != -1; }
76 // Returns the element in the front of the list.
77 const std::string& staged_log() const {
78 DCHECK(has_staged_log());
79 return list_[staged_log_index_].compressed_log_data;
82 // Returns the element in the front of the list.
83 const std::string& staged_log_hash() const {
84 DCHECK(has_staged_log());
85 return list_[staged_log_index_].hash;
88 // The number of elements currently stored.
89 size_t size() const { return list_.size(); }
91 // True if there are no stored logs.
92 bool empty() const { return list_.empty(); }
94 private:
95 // Writes the list to the ListValue.
96 void WriteLogsToPrefList(base::ListValue* list) const;
98 // Reads the list from the ListValue.
99 LogReadStatus ReadLogsFromPrefList(const base::ListValue& list);
101 // A weak pointer to the PrefService object to read and write the preference
102 // from. Calling code should ensure this object continues to exist for the
103 // lifetime of the PersistedLogs object.
104 PrefService* local_state_;
106 // The name of the preference to serialize logs to/from.
107 const char* pref_name_;
109 // We will keep at least this |min_log_count_| logs or |min_log_bytes_| bytes
110 // of logs, whichever is greater, when writing to disk. These apply after
111 // skipping logs greater than |max_log_size_|.
112 const size_t min_log_count_;
113 const size_t min_log_bytes_;
115 // Logs greater than this size will not be written to disk.
116 const size_t max_log_size_;
118 struct LogHashPair {
119 // Initializes the members based on uncompressed |log_data|.
120 void Init(const std::string& log_data);
122 // Compressed log data - a serialized protobuf that's been gzipped.
123 std::string compressed_log_data;
125 // The SHA1 hash of log, stored to catch errors from memory corruption.
126 std::string hash;
128 // A list of all of the stored logs, stored with SHA1 hashes to check for
129 // corruption while they are stored in memory.
130 std::vector<LogHashPair> list_;
132 // The index and type of the log staged for upload. If nothing has been
133 // staged, the index will be -1.
134 int staged_log_index_;
136 DISALLOW_COPY_AND_ASSIGN(PersistedLogs);
139 } // namespace metrics
141 #endif // COMPONENTS_METRICS_PERSISTED_LOGS_H_