C++: Use shared_from_this() exclusively on this

Never call shared_from_this() on any object other than "this".
Adapt the API so that it can be made protected.

diff --git a/bindings/cxx/classes.cpp b/bindings/cxx/classes.cpp
index 960ac39bc0524a5f0ae7f59604f1fa24eeefcee6..2bd2553488a35d4301a90d9dee76f988f7d1faaa 100644 (file)
--- a/bindings/cxx/classes.cpp
+++ b/bindings/cxx/classes.cpp
@@ -159,7 +159,7 @@ map<string, shared_ptr<Driver>> Context::drivers()
        {
                auto name = entry.first;
                auto driver = entry.second;
-               result[name] = driver->get_shared_pointer(this);
+               result[name] = driver->get_shared_pointer(shared_from_this());
        }
        return result;
 }
@@ -171,7 +171,7 @@ map<string, shared_ptr<InputFormat>> Context::input_formats()
        {
                auto name = entry.first;
                auto input_format = entry.second;
-               result[name] = input_format->get_shared_pointer(this);
+               result[name] = input_format->get_shared_pointer(shared_from_this());
        }
        return result;
 }
@@ -183,7 +183,7 @@ map<string, shared_ptr<OutputFormat>> Context::output_formats()
        {
                auto name = entry.first;
                auto output_format = entry.second;
-               result[name] = output_format->get_shared_pointer(this);
+               result[name] = output_format->get_shared_pointer(shared_from_this());
        }
        return result;
 }
@@ -779,7 +779,7 @@ vector<shared_ptr<TriggerStage>> Trigger::stages()
 {
        vector<shared_ptr<TriggerStage>> result;
        for (auto stage : _stages)
-               result.push_back(stage->get_shared_pointer(this));
+               result.push_back(stage->get_shared_pointer(shared_from_this()));
        return result;
 }
 
@@ -787,7 +787,7 @@ shared_ptr<TriggerStage> Trigger::add_stage()
 {
        auto stage = new TriggerStage(sr_trigger_stage_add(_structure));
        _stages.push_back(stage);
-       return stage->get_shared_pointer(this);
+       return stage->get_shared_pointer(shared_from_this());
 }
 
 TriggerStage::TriggerStage(struct sr_trigger_stage *structure) : 
@@ -810,7 +810,7 @@ vector<shared_ptr<TriggerMatch>> TriggerStage::matches()
 {
        vector<shared_ptr<TriggerMatch>> result;
        for (auto match : _matches)
-               result.push_back(match->get_shared_pointer(this));
+               result.push_back(match->get_shared_pointer(shared_from_this()));
        return result;
 }
 
@@ -925,7 +925,7 @@ shared_ptr<Device> Session::get_device(const struct sr_dev_inst *sdi)
 {
        if (_owned_devices.count(sdi))
                return static_pointer_cast<Device>(
-                       _owned_devices[sdi]->get_shared_pointer(this));
+                       _owned_devices[sdi]->get_shared_pointer(shared_from_this()));
        else if (_other_devices.count(sdi))
                return _other_devices[sdi];
        else
@@ -1092,7 +1092,7 @@ const PacketType *Packet::type() const
 shared_ptr<PacketPayload> Packet::payload()
 {
        if (_payload)
-               return _payload->get_shared_pointer(this);
+               return _payload->get_shared_pointer(shared_from_this());
        else
                throw Error(SR_ERR_NA);
 }
@@ -1115,7 +1115,7 @@ Header::~Header()
 {
 }
 
-shared_ptr<PacketPayload> Header::get_shared_pointer(Packet *_parent)
+shared_ptr<PacketPayload> Header::get_shared_pointer(shared_ptr<Packet> _parent)
 {
        return static_pointer_cast<PacketPayload>(
                ParentOwned::get_shared_pointer(_parent));
@@ -1143,7 +1143,7 @@ Meta::~Meta()
 {
 }
 
-shared_ptr<PacketPayload> Meta::get_shared_pointer(Packet *_parent)
+shared_ptr<PacketPayload> Meta::get_shared_pointer(shared_ptr<Packet> _parent)
 {
        return static_pointer_cast<PacketPayload>(
                ParentOwned::get_shared_pointer(_parent));
@@ -1169,7 +1169,7 @@ Logic::~Logic()
 {
 }
 
-shared_ptr<PacketPayload> Logic::get_shared_pointer(Packet *_parent)
+shared_ptr<PacketPayload> Logic::get_shared_pointer(shared_ptr<Packet> _parent)
 {
        return static_pointer_cast<PacketPayload>(
                ParentOwned::get_shared_pointer(_parent));
@@ -1200,7 +1200,7 @@ Analog::~Analog()
 {
 }
 
-shared_ptr<PacketPayload> Analog::get_shared_pointer(Packet *_parent)
+shared_ptr<PacketPayload> Analog::get_shared_pointer(shared_ptr<Packet> _parent)
 {
        return static_pointer_cast<PacketPayload>(
                ParentOwned::get_shared_pointer(_parent));
@@ -1290,8 +1290,7 @@ shared_ptr<Input> InputFormat::create_input(
        auto input = sr_input_new(_structure, map_to_hash_variant(options));
        if (!input)
                throw Error(SR_ERR_ARG);
-       return shared_ptr<Input>(
-               new Input(_parent->shared_from_this(), input), Input::Deleter());
+       return shared_ptr<Input>(new Input(_parent, input), Input::Deleter());
 }
 
 Input::Input(shared_ptr<Context> context, const struct sr_input *structure) :

diff --git a/bindings/cxx/include/libsigrokcxx/libsigrokcxx.hpp b/bindings/cxx/include/libsigrokcxx/libsigrokcxx.hpp
index a83600aa99753d9b4a5baf83ce95a4c4b7de5eaa..38b71a6d10c75cfe0d303f49a974456139e6d22d 100644 (file)
--- a/bindings/cxx/include/libsigrokcxx/libsigrokcxx.hpp
+++ b/bindings/cxx/include/libsigrokcxx/libsigrokcxx.hpp
@@ -164,21 +164,14 @@ protected:
        {
        }
 
-public:
-       /* Get parent object that owns this object. */
-       shared_ptr<Parent> parent()
-       {
-               return _parent;
-       }
-
        /* Note, this implementation will create a new smart_ptr if none exists. */
        shared_ptr<Class> shared_from_this()
        {
-               shared_ptr<Class> shared;
+               shared_ptr<Class> shared = _weak_this.lock();
 
-               if (!(shared = _weak_this.lock()))
+               if (!shared)
                {
-                       shared = shared_ptr<Class>(static_cast<Class *>(this), reset_parent);
+                       shared.reset(static_cast<Class *>(this), &reset_parent);
                        _weak_this = shared;
                }
 
@@ -193,11 +186,11 @@ public:
                return shared_from_this();
        }
 
-       shared_ptr<Class> get_shared_pointer(Parent *parent)
+public:
+       /* Get parent object that owns this object. */
+       shared_ptr<Parent> parent()
        {
-               if (!parent)
-                       throw Error(SR_ERR_BUG);
-               return get_shared_pointer(parent->shared_from_this());
+               return _parent;
        }
 };
 
@@ -205,14 +198,6 @@ public:
 template <class Class, typename Struct>
 class SR_API UserOwned : public enable_shared_from_this<Class>
 {
-public:
-       shared_ptr<Class> shared_from_this()
-       {
-               auto shared = enable_shared_from_this<Class>::shared_from_this();
-               if (!shared)
-                       throw Error(SR_ERR_BUG);
-               return shared;
-       }
 protected:
        Struct *_structure;
 
@@ -221,6 +206,14 @@ protected:
        {
        }
 
+       shared_ptr<Class> shared_from_this()
+       {
+               auto shared = enable_shared_from_this<Class>::shared_from_this();
+               if (!shared)
+                       throw Error(SR_ERR_BUG);
+               return shared;
+       }
+
        /* Deleter needed to allow shared_ptr use with protected destructor. */
        class Deleter
        {
@@ -714,8 +707,15 @@ class SR_API PacketPayload
 protected:
        PacketPayload();
        virtual ~PacketPayload() = 0;
-       virtual shared_ptr<PacketPayload> get_shared_pointer(Packet *parent) = 0;
+private:
+       virtual shared_ptr<PacketPayload> get_shared_pointer(shared_ptr<Packet> parent) = 0;
 
+       /** Deleter needed to allow shared_ptr use with protected destructor. */
+       class Deleter
+       {
+       public:
+               void operator()(PacketPayload *payload) { delete payload; }
+       };
        friend class Deleter;
        friend class Packet;
        friend class Output;
@@ -734,7 +734,7 @@ public:
 private:
        explicit Header(const struct sr_datafeed_header *structure);
        ~Header();
-       shared_ptr<PacketPayload> get_shared_pointer(Packet *parent);
+       shared_ptr<PacketPayload> get_shared_pointer(shared_ptr<Packet> parent);
        friend class Packet;
 };
 
@@ -749,7 +749,7 @@ public:
 private:
        explicit Meta(const struct sr_datafeed_meta *structure);
        ~Meta();
-       shared_ptr<PacketPayload> get_shared_pointer(Packet *parent);
+       shared_ptr<PacketPayload> get_shared_pointer(shared_ptr<Packet> parent);
        map<const ConfigKey *, Glib::VariantBase> _config;
        friend class Packet;
 };
@@ -769,7 +769,7 @@ public:
 private:
        explicit Logic(const struct sr_datafeed_logic *structure);
        ~Logic();
-       shared_ptr<PacketPayload> get_shared_pointer(Packet *parent);
+       shared_ptr<PacketPayload> get_shared_pointer(shared_ptr<Packet> parent);
        friend class Packet;
 };
 
@@ -794,7 +794,7 @@ public:
 private:
        explicit Analog(const struct sr_datafeed_analog *structure);
        ~Analog();
-       shared_ptr<PacketPayload> get_shared_pointer(Packet *parent);
+       shared_ptr<PacketPayload> get_shared_pointer(shared_ptr<Packet> parent);
        friend class Packet;
 };