commit 3054f5ff5a44204c5c372af8847daf2e4f5a6f7d
author Austin Schuh <austin.schuh@bluerivertech.com> Wed Jul 21 15:38:01 2021 -0700
committer Austin Schuh <austin.schuh@bluerivertech.com> Wed Jul 21 15:38:01 2021 -0700
tree 38617e94d84e1264a6fe5d882d1bf7c04eb688d4
parent 479933181ebdc39b6c41cf567d4cb52393ebeffd

Teach ShmEventLoop how to validate some multithreading use cases

This helps catch bugs in callers who do these limited kinds of
multithreading.

Change-Id: Ie04790b2c46f0401430ed4c18a2d10845329623b
Signed-off-by: Austin Schuh <austin.schuh@bluerivertech.com>

aos/events/event_loop.h

diff --git a/aos/events/event_loop.h b/aos/events/event_loop.h
index d23314e..7cb6a5a 100644
--- a/aos/events/event_loop.h
+++ b/aos/events/event_loop.h
@@ -7,6 +7,7 @@
 #include <string>
 #include <string_view>
 
+#include "absl/container/btree_set.h"
 #include "aos/configuration.h"
 #include "aos/configuration_generated.h"
 #include "aos/events/channel_preallocated_allocator.h"
@@ -20,8 +21,6 @@
 #include "aos/time/time.h"
 #include "aos/util/phased_loop.h"
 #include "aos/uuid.h"
-
-#include "absl/container/btree_set.h"
 #include "flatbuffers/flatbuffers.h"
 #include "glog/logging.h"
 
@@ -115,6 +114,7 @@
 
  protected:
   EventLoop *event_loop() { return event_loop_; }
+  const EventLoop *event_loop() const { return event_loop_; }
 
   Context context_;
 
@@ -190,6 +190,7 @@
 
  protected:
   EventLoop *event_loop() { return event_loop_; }
+  const EventLoop *event_loop() const { return event_loop_; }
 
   monotonic_clock::time_point monotonic_sent_time_ = monotonic_clock::min_time;
   realtime_clock::time_point realtime_sent_time_ = realtime_clock::min_time;
@@ -473,8 +474,13 @@
   Ftrace ftrace_;
 };
 
+// Note, it is supported to create only:
+//   multiple fetchers, and (one sender or one watcher) per <name, type>
+//   tuple.
 class EventLoop {
  public:
+  // Holds configuration by reference for the lifetime of this object. It may
+  // never be mutated externally in any way.
   EventLoop(const Configuration *configuration);
 
   virtual ~EventLoop();
@@ -495,10 +501,6 @@
     return GetChannel<T>(channel_name) != nullptr;
   }
 
-  // Note, it is supported to create:
-  //   multiple fetchers, and (one sender or one watcher) per <name, type>
-  //   tuple.
-
   // Makes a class that will always fetch the most recent value
   // sent to the provided channel.
   template <typename T>
@@ -596,7 +598,7 @@
 
   // TODO(austin): OnExit for cleanup.
 
-  // Threadsafe.
+  // May be safely called from any thread.
   bool is_running() const { return is_running_.load(); }
 
   // Sets the scheduler priority to run the event loop at.  This may not be