Add directory.watch.ready for safe torrent watch folders

src/utils/watch_ready_queue.cc

@@ -0,0 +1,158 @@
+#include "config.h"
+
+#include "utils/watch_ready_queue.h"
+
+#include <algorithm>
+#include <torrent/utils/file_stat.h>
+#include <torrent/utils/log.h>
+
+#include "globals.h"
+#include "rpc/rpc_manager.h"
+
+namespace utils {
+
+namespace {
+
+auto compare_next_time = [](const auto* lhs, const auto* rhs) {
+  return lhs->next_time > rhs->next_time;
+};
+
+}
+
+WatchReadyQueue::WatchReadyQueue() {
+  m_task_process.slot() = [this]() { process(); };
+}
+
+WatchReadyQueue::~WatchReadyQueue() {
+  torrent::this_thread::scheduler()->erase(&m_task_process);
+}
+
+void
+WatchReadyQueue::push(const std::string& command, const std::string& path) {
+  if (!m_active)
+    return;
+
+  auto result = m_entries.emplace(path, Entry());
+  auto& entry = result.first->second;
+
+  if (result.second) {
+    entry.path = path;
+    entry.first_seen = torrent::this_thread::cached_time();
+  }
+
+  entry.command = command;
+  entry.last_changed = torrent::this_thread::cached_time();
+  update_status(&entry);
+
+  if (result.second) {
+    update_next_time(&entry);
+    push_entry(&entry);
+  } else {
+    update_entry(&entry);
+  }
+
+  schedule();
+}
+
+void
+WatchReadyQueue::shutdown() {
+  m_active = false;
+  m_entries.clear();
+  m_entry_queue.clear();
+  torrent::this_thread::scheduler()->erase(&m_task_process);
+}
+
+void
+WatchReadyQueue::push_entry(Entry* entry) {
+  m_entry_queue.push_back(entry);
+  std::push_heap(m_entry_queue.begin(), m_entry_queue.end(), compare_next_time);
+}
+
+void
+WatchReadyQueue::update_entry(Entry* entry) {
+  update_next_time(entry);
+  std::make_heap(m_entry_queue.begin(), m_entry_queue.end(), compare_next_time);
+}
+
+void
+WatchReadyQueue::update_next_time(Entry* entry) {
+  if (entry->regular && entry->size > 0) {
+    entry->next_time = entry->last_changed + quiet_time;
+    return;
+  }
+
+  entry->next_time = std::min(torrent::this_thread::cached_time() + retry_time,
+                              entry->first_seen + stale_time);
+}
+
+void
+WatchReadyQueue::update_status(Entry* entry) {
+  torrent::utils::FileStat fs;
+  bool regular = false;
+  int64_t size = -1;
+  time_t mtime = 0;
+
+  if (fs.update(expand_path(entry->path))) {
+    regular = fs.is_regular();
+    size = fs.size();
+    mtime = fs.modified_time();
+  }
+
+  if (entry->regular != regular || entry->size != size || entry->mtime != mtime) {
+    entry->regular = regular;
+    entry->size = size;
+    entry->mtime = mtime;
+    entry->last_changed = torrent::this_thread::cached_time();
+  }
+}
+
+void
+WatchReadyQueue::process() {
+  ready_list ready;
+
+  while (!m_entry_queue.empty() && m_entry_queue.front()->next_time <= torrent::this_thread::cached_time()) {
+    std::pop_heap(m_entry_queue.begin(), m_entry_queue.end(), compare_next_time);
+    Entry* entry = m_entry_queue.back();
+    m_entry_queue.pop_back();
+
+    update_status(entry);
+
+    bool unchanged_entry = torrent::this_thread::cached_time() - entry->last_changed >= quiet_time;
+    bool stale_entry = torrent::this_thread::cached_time() - entry->first_seen >= stale_time;
+    bool nonempty_regular = entry->regular && entry->size > 0;
+
+    if (nonempty_regular && unchanged_entry) {
+      ready.emplace_back(entry->command, entry->path);
+      std::string path = entry->path;
+      m_entries.erase(path);
+      continue;
+    }
+
+    if (!nonempty_regular && stale_entry) {
+      std::string path = entry->path;
+      lt_log_print(torrent::LOG_SYSTEM, "system: Dropped unready watch file after timeout: \"%s\"", path.c_str());
+      m_entries.erase(path);
+      continue;
+    }
+
+    update_next_time(entry);
+    push_entry(entry);
+  }
+
+  schedule();
+
+  for (const auto& item : ready)
+    rpc::commands.call_catch(item.first.c_str(), rpc::make_target(), item.second);
+}
+
+void
+WatchReadyQueue::schedule() {
+  if (m_entry_queue.empty()) {
+    torrent::this_thread::scheduler()->erase(&m_task_process);
+    return;
+  }
+
+  torrent::this_thread::scheduler()->update_wait_until(&m_task_process, m_entry_queue.front()->next_time);
+}
+
+}