FlushCommand.cpp revision 1114f1806521b2a6447b7c68934e4f3c29b60cb5 
1/*
2 * Copyright (C) 2012-2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <stdlib.h>
18
19#include "FlushCommand.h"
20#include "LogBufferElement.h"
21#include "LogCommand.h"
22#include "LogReader.h"
23#include "LogTimes.h"
24
25FlushCommand::FlushCommand(LogReader &reader,
26                           bool nonBlock,
27                           unsigned long tail,
28                           unsigned int logMask,
29                           pid_t pid)
30        : mReader(reader)
31        , mNonBlock(nonBlock)
32        , mTail(tail)
33        , mLogMask(logMask)
34        , mPid(pid)
35{ }
36
37// runSocketCommand is called once for every open client on the
38// log reader socket. Here we manage and associated the reader
39// client tracking and log region locks LastLogTimes list of
40// LogTimeEntrys, and spawn a transitory per-client thread to
41// work at filing data to the  socket.
42//
43// global LogTimeEntry::lock() is used to protect access,
44// reference counts are used to ensure that individual
45// LogTimeEntry lifetime is managed when not protected.
46void FlushCommand::runSocketCommand(SocketClient *client) {
47    LogTimeEntry *entry = NULL;
48    LastLogTimes &times = mReader.logbuf().mTimes;
49
50    LogTimeEntry::lock();
51    LastLogTimes::iterator it = times.begin();
52    while(it != times.end()) {
53        entry = (*it);
54        if (entry->mClient == client) {
55            entry->triggerReader_Locked();
56            if (entry->runningReader_Locked()) {
57                LogTimeEntry::unlock();
58                return;
59            }
60            entry->incRef_Locked();
61            break;
62        }
63        it++;
64    }
65
66    if (it == times.end()) {
67        // Create LogTimeEntry in notifyNewLog() ?
68        if (mTail == (unsigned long) -1) {
69            LogTimeEntry::unlock();
70            return;
71        }
72        entry = new LogTimeEntry(mReader, client, mNonBlock, mTail, mLogMask, mPid);
73        times.push_back(entry);
74    }
75
76    client->incRef();
77
78    // release client and entry reference counts once done
79    entry->startReader_Locked();
80    LogTimeEntry::unlock();
81}
82
83bool FlushCommand::hasReadLogs(SocketClient *client) {
84    return clientHasLogCredentials(client);
85}
86