[io] Implement blocking IODevice for fibers

Author: salkinium

src/modm/io/iodevice_wrapper.hpp renamed to src/modm/io/iodevice_wrapper.hpp.in

@@ -16,7 +16,10 @@
 #define MODM_IODEVICE_WRAPPER_HPP
 
 #include <stdint.h>
-
+%% if with_fiber
+#include <modm/processing/fiber.hpp>
+%% endif
+%#
 #include "iodevice.hpp"
 
 namespace modm
@@ -39,19 +42,34 @@ IOBuffer
 template< class Device, IOBuffer behavior >
 class IODeviceWrapper : public IODevice
 {
+%% if with_fiber
+	static constexpr fiber::id NoOwner{fiber::id(-1)};
+	static inline fiber::id id{NoOwner};
+%% endif
 public:
 	IODeviceWrapper() = default;
 	using IODevice::write;
 
 	void
 	write(char c) override
 	{
-		bool written;
-		do
+		if constexpr (behavior == IOBuffer::BlockIfFull)
+%% if with_fiber
 		{
-			written = Device::write(uint8_t(c));
+			// lock this device to one fiber until a newline is received
+			const auto me = modm::this_fiber::get_id();
+			modm::this_fiber::poll([&]{ return id == NoOwner or id == me; });
+			id = me;
+
+			modm::this_fiber::poll([&]{ return Device::write(uint8_t(c)); });
+
+			if (c == '\n') id = NoOwner;
+			modm::this_fiber::yield();
 		}
-		while(behavior == IOBuffer::BlockIfFull and not written);
+%% else
+			while (not Device::write(uint8_t(c))) ;
+%% endif
+		else Device::write(uint8_t(c));
 	}
 
 	void
@@ -71,6 +89,10 @@ class IODeviceWrapper : public IODevice
 template< class Device, IOBuffer behavior >
 class IODeviceObjectWrapper : public IODevice
 {
+%% if with_fiber
+	static constexpr fiber::id NoOwner{fiber::id(-1)};
+	fiber::id id{NoOwner};
+%% endif
 	Device &device;
 public:
 	IODeviceObjectWrapper(Device& device) : device{device} {}
@@ -79,12 +101,23 @@ class IODeviceObjectWrapper : public IODevice
 	void
 	write(char c) override
 	{
-		bool written;
-		do
+		if constexpr (behavior == IOBuffer::BlockIfFull)
+%% if with_fiber
 		{
-			written = device.write(uint8_t(c));
+			// lock this device to one fiber until a newline is received
+			const auto me = modm::this_fiber::get_id();
+			modm::this_fiber::poll([&]{ return id == NoOwner or id == me; });
+			id = me;
+
+			modm::this_fiber::poll([&]{ return device.write(uint8_t(c)); });
+
+			if (c == '\n') id = NoOwner;
+			modm::this_fiber::yield();
 		}
-		while(behavior == IOBuffer::BlockIfFull and not written);
+%% else
+			while (not device.write(uint8_t(c))) ;
+%% endif
+		else device.write(uint8_t(c));
 	}
 
 	void

src/modm/io/module.lb

@@ -18,6 +18,7 @@ def init(module):
 def prepare(module, options):
     module.depends(
         ":architecture:accessor",
+        ":architecture:fiber",
         ":math:utils")
 
     is_avr = options[":target"].identifier.platform in ["avr"]
@@ -45,12 +46,13 @@ def build(env):
     env.substitutions = {
         "is_hosted": target.platform == "hosted",
         "is_avr": target.platform == "avr",
+        "with_fiber": env.has_module(":processing:fiber"),
         "family": target.family,
         "core": core,
     }
     env.outbasepath = "modm/src/modm/io"
     env.copy("iodevice.hpp")
-    env.copy("iodevice_wrapper.hpp")
+    env.template("iodevice_wrapper.hpp.in")
     env.template("iostream_printf.cpp.in")
     env.template("iostream.hpp.in")
     env.template("iostream_chrono.hpp.in")