From 9aaba1211c95dc7e08437a7cca73452181e296d6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Roman=20Smr=C5=BE?= <roman.smrz@seznam.cz>
Date: Sun, 18 Apr 2021 22:25:17 +0200
Subject: Initial support for FRP behaviors

---
 src/CMakeLists.txt |   1 +
 src/frp.cpp        | 133 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/identity.cpp   |  10 ++++
 src/network.cpp    |   6 +++
 src/network.h      |   1 +
 5 files changed, 151 insertions(+)
 create mode 100644 src/frp.cpp

(limited to 'src')

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 61f491f..8f65555 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -5,6 +5,7 @@ include_directories(
 add_library(erebos
 	attach
 	channel
+	frp
 	identity
 	message
 	network
diff --git a/src/frp.cpp b/src/frp.cpp
new file mode 100644
index 0000000..142fcd4
--- /dev/null
+++ b/src/frp.cpp
@@ -0,0 +1,133 @@
+#include <erebos/frp.h>
+
+#include <condition_variable>
+#include <mutex>
+
+using namespace erebos;
+
+using std::condition_variable;
+using std::move;
+using std::mutex;
+using std::nullopt;
+using std::unique_lock;
+using std::weak_ptr;
+
+mutex bhvTimeMutex;
+condition_variable bhvTimeCond;
+bool bhvTimeRunning = false;
+uint64_t bhvTimeLast = 0;
+
+BhvCurTime::BhvCurTime()
+{
+	unique_lock lock(bhvTimeMutex);
+	bhvTimeCond.wait(lock, []{ return !bhvTimeRunning; });
+
+	bhvTimeRunning = true;
+	t = BhvTime(++bhvTimeLast);
+}
+
+BhvCurTime::~BhvCurTime()
+{
+	if (t) {
+		unique_lock lock(bhvTimeMutex);
+		bhvTimeRunning = false;
+		lock.unlock();
+		bhvTimeCond.notify_one();
+	}
+}
+
+BhvCurTime::BhvCurTime(BhvCurTime && other)
+{
+	t = other.t;
+	other.t = nullopt;
+}
+
+BhvCurTime & BhvCurTime::operator=(BhvCurTime && other)
+{
+	t = other.t;
+	other.t = nullopt;
+	return *this;
+}
+
+
+BhvImplBase::~BhvImplBase() = default;
+
+void BhvImplBase::dependsOn(shared_ptr<BhvImplBase> other)
+{
+	depends.push_back(other);
+	other->rdepends.push_back(shared_from_this());
+}
+
+void BhvImplBase::updated(const BhvCurTime & ctime)
+{
+	vector<shared_ptr<BhvImplBase>> toUpdate;
+	markDirty(ctime, toUpdate);
+
+	for (auto & bhv : toUpdate)
+		bhv->updateDirty(ctime);
+}
+
+void BhvImplBase::markDirty(const BhvCurTime & ctime, vector<shared_ptr<BhvImplBase>> & toUpdate)
+{
+	if (dirty)
+		return;
+
+	if (!needsUpdate(ctime))
+		return;
+
+	dirty = true;
+	toUpdate.push_back(shared_from_this());
+
+	bool prune = false;
+	for (const auto & w : rdepends) {
+		if (auto b = w.lock())
+			b->markDirty(ctime, toUpdate);
+		else
+			prune = true;
+	}
+
+	if (prune) {
+		decltype(rdepends) pruned;
+		for (const auto & w : rdepends)
+			if (!w.expired())
+				pruned.push_back(move(w));
+		rdepends = move(pruned);
+	}
+}
+
+void BhvImplBase::updateDirty(const BhvCurTime & ctime)
+{
+	if (!dirty)
+		return;
+
+	for (auto & d : depends)
+		d->updateDirty(ctime);
+
+	doUpdate(ctime);
+	dirty = false;
+
+	bool prune = false;
+	for (const auto & wcb : watchers) {
+		if (auto cb = wcb.lock())
+			(*cb)(ctime);
+		else
+			prune = true;
+	}
+
+	if (prune) {
+		decltype(watchers) pruned;
+		for (const auto & w : watchers)
+			if (!w.expired())
+				pruned.push_back(move(w));
+		watchers = move(pruned);
+	}
+}
+
+bool BhvImplBase::needsUpdate(const BhvCurTime &) const
+{
+	return true;
+}
+
+void BhvImplBase::doUpdate(const BhvCurTime &)
+{
+}
diff --git a/src/identity.cpp b/src/identity.cpp
index 374a872..a4c12f2 100644
--- a/src/identity.cpp
+++ b/src/identity.cpp
@@ -77,6 +77,16 @@ bool Identity::sameAs(const Identity & other) const
 		other.p->data[0]->data->keyIdentity;
 }
 
+bool Identity::operator==(const Identity & other) const
+{
+	return p->data == other.p->data;
+}
+
+bool Identity::operator!=(const Identity & other) const
+{
+	return p->data != other.p->data;
+}
+
 optional<Ref> Identity::ref() const
 {
 	if (p->data.size() == 1)
diff --git a/src/network.cpp b/src/network.cpp
index f33c097..259ae5e 100644
--- a/src/network.cpp
+++ b/src/network.cpp
@@ -38,6 +38,11 @@ const Head<LocalState> & Server::localHead() const
 	return p->localHead;
 }
 
+const Bhv<LocalState> & Server::localState() const
+{
+	return p->localState;
+}
+
 const Identity & Server::identity() const
 {
 	return p->self;
@@ -203,6 +208,7 @@ Server::Priv::Priv(const Head<LocalState> & local, const Identity & self,
 		vector<unique_ptr<Service>> && svcs):
 	self(self),
 	// Watching needs to start after self is initialized
+	localState(local.behavior()),
 	localHead(local.watch(std::bind(&Priv::handleLocalHeadChange, this, std::placeholders::_1))),
 	services(std::move(svcs))
 {
diff --git a/src/network.h b/src/network.h
index 6ebd60c..fe7d7b4 100644
--- a/src/network.h
+++ b/src/network.h
@@ -158,6 +158,7 @@ struct Server::Priv : enable_shared_from_this<Server::Priv>
 	bool finish = false;
 
 	Identity self;
+	Bhv<LocalState> localState;
 	WatchedHead<LocalState> localHead;
 	vector<unique_ptr<Service>> services;
 
-- 
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