[libcamera-devel] [PATCH 2/2] libcamera: message: Add user message types

[Laurent Pinchart]

Hi Jacopo,

On Tue, Jul 16, 2019 at 09:39:24AM +0200, Jacopo Mondi wrote:
> On Mon, Jul 15, 2019 at 12:29:39PM +0300, Laurent Pinchart wrote:
> > From: Jacopo Mondi <jacopo at jmondi.org>
> >
> > Reserve identifiers for user-defined message types and add an operation
> > to the Message class to create register the type identifiers.
> 
> create 'and' register ?

Oops :-) Will fix.

> Otherwise
> Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>
> 
> > Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> > Changes since v1:
> >
> > - Replace mutex with atomic
> > - Rework documentation
> > - Rename registerUserMessageType() to registerMessageType()
> > - Extend the Message test
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> >  src/libcamera/include/message.h |  7 +++++++
> >  src/libcamera/message.cpp       | 36 +++++++++++++++++++++++++++++++++
> >  test/message.cpp                | 11 ++++++++++
> >  3 files changed, 54 insertions(+)
> >
> > diff --git a/src/libcamera/include/message.h b/src/libcamera/include/message.h
> > index db17d647c280..416fe74b10ad 100644
> > --- a/src/libcamera/include/message.h
> > +++ b/src/libcamera/include/message.h
> > @@ -7,6 +7,8 @@
> >  #ifndef __LIBCAMERA_MESSAGE_H__
> >  #define __LIBCAMERA_MESSAGE_H__
> >
> > +#include <atomic>
> > +
> >  namespace libcamera {
> >
> >  class Object;
> > @@ -19,6 +21,7 @@ public:
> >  	enum Type {
> >  		None = 0,
> >  		SignalMessage = 1,
> > +		UserMessage = 1000,
> >  	};
> >
> >  	Message(Type type);
> > @@ -27,11 +30,15 @@ public:
> >  	Type type() const { return type_; }
> >  	Object *receiver() const { return receiver_; }
> >
> > +	static Type registerMessageType();
> > +
> >  private:
> >  	friend class Thread;
> >
> >  	Type type_;
> >  	Object *receiver_;
> > +
> > +	static std::atomic_uint nextUserType_;
> >  };
> >
> >  class SignalMessage : public Message
> > diff --git a/src/libcamera/message.cpp b/src/libcamera/message.cpp
> > index 9f22ad7fc0b0..d44d2a4c73a8 100644
> > --- a/src/libcamera/message.cpp
> > +++ b/src/libcamera/message.cpp
> > @@ -31,6 +31,8 @@ namespace libcamera {
> >
> >  LOG_DEFINE_CATEGORY(Message)
> >
> > +std::atomic_uint Message::nextUserType_{ Message::UserMessage };
> > +
> >  /**
> >   * \class Message
> >   * \brief A message that can be posted to a Thread
> > @@ -43,6 +45,8 @@ LOG_DEFINE_CATEGORY(Message)
> >   * \brief Invalid message type
> >   * \var Message::SignalMessage
> >   * \brief Asynchronous signal delivery across threads
> > + * \var Message::UserMessage
> > + * \brief First value available for user-defined messages
> >   */
> >
> >  /**
> > @@ -70,6 +74,38 @@ Message::~Message()
> >   * \return The message receiver
> >   */
> >
> > +/**
> > + * \brief Reserve and register a custom user-defined message type
> > + *
> > + * Custom message types use values starting at Message::UserMessage. Assigning
> > + * custom types manually may lead to accidental duplicated types. To avoid this
> > + * problem, this method reserves and returns the next available user-defined
> > + * message type.
> > + *
> > + * The recommended way to use this method is to subclass Message and provide a
> > + * static accessor for the custom message type.
> > + *
> > + * \code{.cpp}
> > + * class MyCustomMessage : public Message
> > + * {
> > + * public:
> > + *	MyCustomMessage() : Message(type()) { }
> > + *
> > + *	static Message::Type type()
> > + *	{
> > + *		static MessageType type = registerMessageType();
> > + *		return type;
> > + *	}
> > + * };
> > + * \endcode
> > + *
> > + * \return A new unique message type
> > + */
> > +Message::Type Message::registerMessageType()
> > +{
> > +	return static_cast<Message::Type>(nextUserType_++);
> > +}
> > +
> >  /**
> >   * \class SignalMessage
> >   * \brief A message carrying a Signal across threads
> > diff --git a/test/message.cpp b/test/message.cpp
> > index de98da3e8754..3775c30a20b3 100644
> > --- a/test/message.cpp
> > +++ b/test/message.cpp
> > @@ -52,6 +52,17 @@ class MessageTest : public Test
> >  protected:
> >  	int run()
> >  	{
> > +		Message::Type msgType[2] = {
> > +			Message::registerMessageType(),
> > +			Message::registerMessageType(),
> > +		};
> > +
> > +		if (msgType[0] != Message::UserMessage ||
> > +		    msgType[1] != Message::UserMessage + 1) {
> > +			cout << "Failed to register message types" << endl;
> > +			return TestFail;
> > +		}
> > +
> >  		MessageReceiver receiver;
> >  		receiver.moveToThread(&thread_);
> >

-- 
Regards,

Laurent Pinchart