git.sesse.net Git - casparcg/blob - common/polling_filesystem_monitor.cpp

   1 /*
   2 * Copyright (c) 2011 Sveriges Television AB <info@casparcg.com>
   3 *
   4 * This file is part of CasparCG (www.casparcg.com).
   5 *
   6 * CasparCG is free software: you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation, either version 3 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * CasparCG is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with CasparCG. If not, see <http://www.gnu.org/licenses/>.
  18 *
  19 * Author: Helge Norberg, helge.norberg@svt.se
  20 */
  21
  22 #include "stdafx.h"
  23
  24 #include "polling_filesystem_monitor.h"
  25
  26 #include <map>
  27 #include <set>
  28 #include <iostream>
  29 #include <cstdint>
  30
  31 #include <boost/thread.hpp>
  32 #include <boost/filesystem/fstream.hpp>
  33 #include <boost/filesystem/convenience.hpp>
  34
  35 #include <tbb/atomic.h>
  36 #include <tbb/concurrent_queue.h>
  37
  38 #include "executor.h"
  39 #include "linq.h"
  40
  41 namespace caspar {
  42
  43 class exception_protected_handler
  44 {
  45         filesystem_monitor_handler handler_;
  46 public:
  47         exception_protected_handler(const filesystem_monitor_handler& handler)
  48                 : handler_(handler)
  49         {
  50         }
  51
  52         void operator()(filesystem_event event, const boost::filesystem::wpath& file)
  53         {
  54                 try
  55                 {
  56                         boost::this_thread::interruption_point();
  57                         handler_(event, file);
  58                         boost::this_thread::interruption_point();
  59                 }
  60                 catch (const boost::thread_interrupted&)
  61                 {
  62                         throw;
  63                 }
  64                 catch (...)
  65                 {
  66                         CASPAR_LOG_CURRENT_EXCEPTION();
  67                 }
  68         }
  69 };
  70
  71 class directory_monitor
  72 {
  73         bool                                                                                    report_already_existing_;
  74         boost::filesystem::wpath                                                folder_;
  75         filesystem_event                                                                events_mask_;
  76         filesystem_monitor_handler                                              handler_;
  77         initial_files_handler                                                   initial_files_handler_;
  78         bool                                                                                    first_scan_                                     = true;
  79         std::map<boost::filesystem::wpath, std::time_t> files_;
  80         std::map<boost::filesystem::wpath, uintmax_t>   being_written_sizes_;
  81 public:
  82         directory_monitor(
  83                         bool report_already_existing,
  84                         const boost::filesystem::wpath& folder,
  85                         filesystem_event events_mask,
  86                         const filesystem_monitor_handler& handler,
  87                         const initial_files_handler& initial_files_handler)
  88                 : report_already_existing_(report_already_existing)
  89                 , folder_(folder)
  90                 , events_mask_(events_mask)
  91                 , handler_(exception_protected_handler(handler))
  92                 , initial_files_handler_(initial_files_handler)
  93         {
  94         }
  95
  96         void reemmit_all()
  97         {
  98                 if (static_cast<int>(events_mask_ & filesystem_event::MODIFIED) == 0)
  99                         return;
 100
 101                 for (auto& file : files_)
 102                         handler_(filesystem_event::MODIFIED, file.first);
 103         }
 104
 105         void reemmit(const boost::filesystem::wpath& file)
 106         {
 107                 if (static_cast<int>(events_mask_ & filesystem_event::MODIFIED) == 0)
 108                         return;
 109
 110                 if (files_.find(file) != files_.end() && boost::filesystem::exists(file))
 111                         handler_(filesystem_event::MODIFIED, file);
 112         }
 113
 114         void scan(const boost::function<bool ()>& should_abort)
 115         {
 116                 static const std::time_t NO_LONGER_WRITING_AGE = 3; // Assume std::time_t is expressed in seconds
 117                 using namespace boost::filesystem;
 118
 119                 bool interested_in_removed = static_cast<int>(events_mask_ & filesystem_event::REMOVED) > 0;
 120                 bool interested_in_created = static_cast<int>(events_mask_ & filesystem_event::CREATED) > 0;
 121                 bool interested_in_modified = static_cast<int>(events_mask_ & filesystem_event::MODIFIED) > 0;
 122
 123                 auto filenames = cpplinq::from(files_).select(keys());
 124                 std::set<wpath> removed_files(filenames.begin(), filenames.end());
 125                 std::set<wpath> initial_files;
 126
 127                 for (boost::filesystem::wrecursive_directory_iterator iter(folder_); iter != boost::filesystem::wrecursive_directory_iterator(); ++iter)
 128                 {
 129                         if (should_abort())
 130                                 return;
 131
 132                         auto& path = iter->path();
 133
 134                         if (is_directory(path))
 135                                 continue;
 136
 137                         auto now = std::time(nullptr);
 138                         std::time_t current_mtime;
 139
 140                         try
 141                         {
 142                                 current_mtime = last_write_time(path);
 143                         }
 144                         catch (...)
 145                         {
 146                                 // Probably removed, will be captured the next round.
 147                                 continue;
 148                         }
 149
 150                         auto time_since_written_to = now - current_mtime;
 151                         bool no_longer_being_written_to = time_since_written_to >= NO_LONGER_WRITING_AGE;
 152                         auto previous_it = files_.find(path);
 153                         bool already_known = previous_it != files_.end();
 154
 155                         if (already_known && no_longer_being_written_to)
 156                         {
 157                                 bool modified = previous_it->second != current_mtime;
 158
 159                                 if (modified && can_read_file(path))
 160                                 {
 161                                         if (interested_in_modified)
 162                                                 handler_(filesystem_event::MODIFIED, path);
 163
 164                                         files_[path] = current_mtime;
 165                                         being_written_sizes_.erase(path);
 166                                 }
 167                         }
 168                         else if (no_longer_being_written_to && can_read_file(path))
 169                         {
 170                                 if (interested_in_created && (report_already_existing_ || !first_scan_))
 171                                         handler_(filesystem_event::CREATED, path);
 172
 173                                 if (first_scan_)
 174                                         initial_files.insert(path);
 175
 176                                 files_.insert(std::make_pair(path, current_mtime));
 177                                 being_written_sizes_.erase(path);
 178                         }
 179
 180                         removed_files.erase(path);
 181                 }
 182
 183                 for (auto& path : removed_files)
 184                 {
 185                         files_.erase(path);
 186                         being_written_sizes_.erase(path);
 187
 188                         if (interested_in_removed)
 189                                 handler_(filesystem_event::REMOVED, path);
 190                 }
 191
 192                 if (first_scan_)
 193                         initial_files_handler_(initial_files);
 194
 195                 first_scan_ = false;
 196         }
 197 private:
 198         bool can_read_file(const boost::filesystem::wpath& file)
 199         {
 200                 boost::filesystem::wifstream stream(file);
 201
 202                 return stream.is_open();
 203         }
 204 };
 205
 206 class polling_filesystem_monitor : public filesystem_monitor
 207 {
 208         directory_monitor root_monitor_;
 209         boost::thread scanning_thread_;
 210         tbb::atomic<bool> running_;
 211         int scan_interval_millis_;
 212         std::promise<void> initial_scan_completion_;
 213         tbb::concurrent_queue<boost::filesystem::wpath> to_reemmit_;
 214         tbb::atomic<bool> reemmit_all_;
 215 public:
 216         polling_filesystem_monitor(
 217                         const boost::filesystem::wpath& folder_to_watch,
 218                         filesystem_event events_of_interest_mask,
 219                         bool report_already_existing,
 220                         int scan_interval_millis,
 221                         const filesystem_monitor_handler& handler,
 222                         const initial_files_handler& initial_files_handler)
 223                 : root_monitor_(report_already_existing, folder_to_watch, events_of_interest_mask, handler, initial_files_handler)
 224                 , scan_interval_millis_(scan_interval_millis)
 225         {
 226                 running_ = true;
 227                 reemmit_all_ = false;
 228                 scanning_thread_ = boost::thread([this] { scanner(); });
 229         }
 230
 231         virtual ~polling_filesystem_monitor()
 232         {
 233                 running_ = false;
 234                 scanning_thread_.interrupt();
 235                 scanning_thread_.join();
 236         }
 237
 238         virtual std::future<void> initial_files_processed()
 239         {
 240                 return initial_scan_completion_.get_future();
 241         }
 242
 243         virtual void reemmit_all()
 244         {
 245                 reemmit_all_ = true;
 246         }
 247
 248         virtual void reemmit(const boost::filesystem::wpath& file)
 249         {
 250                 to_reemmit_.push(file);
 251         }
 252 private:
 253         void scanner()
 254         {
 255                 win32_exception::install_handler();
 256
 257                 //detail::SetThreadName(GetCurrentThreadId(), "polling_filesystem_monitor");
 258
 259                 bool running = scan(false);
 260                 initial_scan_completion_.set_value();
 261
 262                 if (running)
 263                         while (scan(true));
 264         }
 265
 266         bool scan(bool sleep)
 267         {
 268                 try
 269                 {
 270                         if (sleep)
 271                                 boost::this_thread::sleep(boost::posix_time::milliseconds(scan_interval_millis_));
 272
 273                         if (reemmit_all_.fetch_and_store(false))
 274                                 root_monitor_.reemmit_all();
 275                         else
 276                         {
 277                                 boost::filesystem::wpath file;
 278
 279                                 while (to_reemmit_.try_pop(file))
 280                                         root_monitor_.reemmit(file);
 281                         }
 282
 283                         root_monitor_.scan([=] { return !running_; });
 284                 }
 285                 catch (const boost::thread_interrupted&)
 286                 {
 287                 }
 288                 catch (...)
 289                 {
 290                         CASPAR_LOG_CURRENT_EXCEPTION();
 291                 }
 292
 293                 return running_;
 294         }
 295 };
 296
 297 struct polling_filesystem_monitor_factory::impl
 298 {
 299         int scan_interval_millis;
 300
 301         impl(int scan_interval_millis)
 302                 : scan_interval_millis(scan_interval_millis)
 303         {
 304         }
 305 };
 306
 307 polling_filesystem_monitor_factory::polling_filesystem_monitor_factory(int scan_interval_millis)
 308         : impl_(new impl(scan_interval_millis))
 309 {
 310 }
 311
 312 polling_filesystem_monitor_factory::~polling_filesystem_monitor_factory()
 313 {
 314 }
 315
 316 filesystem_monitor::ptr polling_filesystem_monitor_factory::create(
 317                 const boost::filesystem::wpath& folder_to_watch,
 318                 filesystem_event events_of_interest_mask,
 319                 bool report_already_existing,
 320                 const filesystem_monitor_handler& handler,
 321                 const initial_files_handler& initial_files_handler)
 322 {
 323         return spl::make_shared<polling_filesystem_monitor>(
 324                         folder_to_watch,
 325                         events_of_interest_mask,
 326                         report_already_existing,
 327                         impl_->scan_interval_millis,
 328                         handler,
 329                         initial_files_handler);
 330 }
 331
 332 }