Add a printf-style interface for formatted output

Author: tdz

Makefile

@@ -75,6 +75,7 @@ OBJ := $(addprefix $(OBJDIR)/src/, \
 	pinmux.o \
 	Producer.o \
 	Serial.o \
+	SerialIO.o \
 	Task.o \
 	)
 

src/Producer.c

@@ -3,11 +3,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "Producer.h"
-
-#include <string.h>
-
-#include "IPCQueue.h"
 #include "Ptr.h"
+#include "SerialIO.h"
 #include "Task.h"
 #include "Ticks.h"
 
@@ -18,36 +15,9 @@ Run(ProducerTask* aProducer)
     "This"," is"," a"," SensorWeb"," device"," by"," Mozilla.\n\r"
   };
 
-  IPCMessage msg;
-  int res = IPCMessageInit(&msg);
-  if (res < 0) {
-    return;
-  }
-
   for (unsigned long i = 0;; i = (i + 1) % ArrayLength(sMessage)) {
-
-    res = IPCMessageProduce(&msg, strlen(sMessage[i]) + 1, (void*)sMessage[i]);
-    if (res < 0) {
-      return;
-    }
-    /* no need to synchronize over static constant buffer */
-    msg.mStatus |= IPC_MESSAGE_FLAG_NOWAIT;
-
-    res = IPCMessageQueueConsume(aProducer->mSendQueue, &msg);
-    if (res < 0) {
-      return;
-    }
-
+    print("%s", sMessage[i]);
     vTaskDelay(TicksOfMSecs(200));
-
-    /* While we have been waiting in vTaskDelay(), the consumer
-     * probably processed our message. Waiting for consumption is
-     * only a formality here, as we set the NOWAIT flag.
-     */
-    res = IPCMessageWaitForConsumption(&msg);
-    if (res < 0) {
-      return;
-    }
   }
 }
 
@@ -65,9 +35,8 @@ TaskEntryPoint(void* aParam)
 }
 
 int
-ProducerTaskInit(ProducerTask* aProducer, IPCMessageQueue* aSendQueue)
+ProducerTaskInit(ProducerTask* aProducer)
 {
-  aProducer->mSendQueue = aSendQueue;
   aProducer->mTask = NULL;
 
   return 0;

src/Producer.h

@@ -5,20 +5,15 @@
 #pragma once
 
 #include <FreeRTOS.h>
-#include <queue.h>
 #include <task.h>
 
-#include "IPCQueue.h"
-
 typedef struct
 {
-  IPCMessageQueue* mSendQueue;
-
   TaskHandle_t mTask;
 } ProducerTask;
 
 int
-ProducerTaskInit(ProducerTask* aProducer, IPCMessageQueue* aSendQueue);
+ProducerTaskInit(ProducerTask* aProducer);
 
 int
 ProducerTaskSpawn(ProducerTask* aProducer);

src/Serial.c

@@ -4,10 +4,23 @@
 
 #include "Serial.h"
 
+#include <FreeRTOS.h>
+#include <task.h>
 #include <uart_if.h>
 
 #include "Task.h"
 
+/*
+ * Serial output
+ */
+
+typedef struct
+{
+  IPCMessageQueue mRecvQueue;
+
+  TaskHandle_t mTask;
+} SerialOutTask;
+
 static void
 Run(SerialOutTask* aSerialOut)
 {
@@ -39,7 +52,7 @@ TaskEntryPoint(void* aParam)
   vTaskSuspend(serialOut->mTask);
 }
 
-int
+static int
 SerialOutTaskInit(SerialOutTask* aSerialOut)
 {
   int res = IPCMessageQueueInit(&aSerialOut->mRecvQueue);
@@ -51,7 +64,7 @@ SerialOutTaskInit(SerialOutTask* aSerialOut)
   return 0;
 }
 
-int
+static int
 SerialOutTaskSpawn(SerialOutTask* aSerialOut)
 {
   BaseType_t res = xTaskCreate(TaskEntryPoint, "serial-out",
@@ -62,3 +75,30 @@ SerialOutTaskSpawn(SerialOutTask* aSerialOut)
   }
   return 0;
 }
+
+/*
+ * Public interfaces
+ */
+
+static SerialOutTask sSerialOutTask;
+
+int
+SerialInit()
+{
+  /*
+   * Create the output task
+   */
+  if (SerialOutTaskInit(&sSerialOutTask) < 0) {
+    return -1;
+  }
+  if (SerialOutTaskSpawn(&sSerialOutTask) < 0) {
+    return -1;
+  }
+  return 0;
+}
+
+IPCMessageQueue*
+GetSerialOutQueue()
+{
+  return &sSerialOutTask.mRecvQueue;
+}

src/Serial.h

@@ -4,21 +4,13 @@
 
 #pragma once
 
-#include <FreeRTOS.h>
-#include <queue.h>
-#include <task.h>
-
 #include "IPCQueue.h"
 
-typedef struct
-{
-  IPCMessageQueue mRecvQueue;
-
-  TaskHandle_t mTask;
-} SerialOutTask;
-
 int
-SerialOutTaskInit(SerialOutTask* aSerialOut);
+SerialInit(void);
 
-int
-SerialOutTaskSpawn(SerialOutTask* aSerialOut);
+/* Returns the message queue for output of over the serial line. This
+ * is a singleton.
+ */
+IPCMessageQueue*
+GetSerialOutQueue(void);

src/SerialIO.c

@@ -0,0 +1,58 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "SerialIO.h"
+#include <stdio.h>
+#include "Serial.h"
+
+static int
+Print(uint32_t aLength, void* aBuffer)
+{
+  IPCMessageQueue* queue = GetSerialOutQueue();
+  if (!queue) {
+    return -1;
+  }
+
+  IPCMessage msg;
+  int res = IPCMessageInit(&msg);
+  if (res < 0) {
+    return -1;
+  }
+  res = IPCMessageProduce(&msg, aLength, aBuffer);
+  if (res < 0) {
+    return -1;
+  }
+  res = IPCMessageQueueConsume(queue, &msg);
+  if (res < 0) {
+    return -1;
+  }
+  return IPCMessageWaitForConsumption(&msg);
+}
+
+/*
+ * Libc-like interfaces for easy usage.
+ */
+
+int
+print(const char* fmt, ...)
+{
+  va_list ap;
+
+  va_start(ap, fmt);
+  int res = vprint(fmt, ap);
+  va_end(ap);
+
+  return res;
+}
+
+int
+vprint(const char* fmt, va_list ap)
+{
+  char buf[128];
+  int res = vsnprintf(buf, sizeof(buf), fmt, ap);
+  if (res < 0) {
+    return -1;
+  }
+  return Print(sizeof(buf), buf);
+}

src/SerialIO.h

@@ -0,0 +1,13 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#pragma once
+
+#include <stdarg.h>
+
+int
+print(const char* fmt, ...);
+
+int
+vprint(const char* fmt, va_list ap);

src/main.c

@@ -37,12 +37,7 @@ main(void)
    * Create the output task
    */
 
-  static SerialOutTask serialOutTask;
-
-  if (SerialOutTaskInit(&serialOutTask) < 0) {
-    return EXIT_FAILURE;
-  }
-  if (SerialOutTaskSpawn(&serialOutTask) < 0) {
+  if (SerialInit() < 0) {
     return EXIT_FAILURE;
   }
 
@@ -52,7 +47,7 @@ main(void)
 
   static ProducerTask producerTask;
 
-  if (ProducerTaskInit(&producerTask, &serialOutTask.mRecvQueue) < 0) {
+  if (ProducerTaskInit(&producerTask) < 0) {
     return EXIT_FAILURE;
   }
   if (ProducerTaskSpawn(&producerTask) < 0) {