Added an example of using the Coffee file system.

examples/sky/example-coffee.c

@@ -0,0 +1,182 @@
+/*
+ * Copyright (c) 2011, Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * This file is part of the Contiki operating system.
+ */
+
+/**
+ * \file
+ *         Example on how to use CFS/Coffee.
+ * \author
+ *         Nicolas Tsiftes <nvt@sics.se>
+ */
+
+#include <stdio.h>
+
+#include "contiki.h"
+#include "cfs/cfs.h"
+#include "cfs/cfs-coffee.h"
+
+PROCESS(example_coffee_process, "Coffee example");
+AUTOSTART_PROCESSES(&example_coffee_process);
+
+#define FILENAME "test"
+
+/* Formatting is needed if the storage device is in an unknown state; 
+   e.g., when using Coffee on the storage device for the first time. */
+#ifndef NEED_FORMATTING
+#define NEED_FORMATTING 0
+#endif
+
+static int
+file_test(const char *filename, char *msg)
+{
+  static uint8_t sequence;
+  int fd;
+  int r;
+  struct record {
+    char message[16];
+    uint8_t sequence;
+  } record;
+
+  /*
+   * Coffee determines the file length by finding the last non-zero byte 
+   * of the file. This I/O semantic requires that each record should end 
+   * with a non-zero, if we are writing multiple records and closing the 
+   * file descriptor in between.
+   *
+   * In this example, in which the file_test function can be called 
+   * multiple times, we ensure that the sequence counter starts at 1.
+   */
+
+  if(sequence == 255) {
+    /* No more sequence numbers available. */
+    return -1;
+  }
+  sequence++;
+
+  strncpy(record.message, msg, sizeof(record.message) - 1);
+  record.message[sizeof(record.message) - 1] = '\0';
+  record.sequence = sequence;
+
+  /* Obtain a file descriptor for the file, capable of handling both 
+     reads and writes. */
+  fd = cfs_open(FILENAME, CFS_WRITE | CFS_APPEND | CFS_READ);
+  if(fd < 0) {
+    printf("failed to open %s\n", FILENAME);
+    return 0;
+  }
+
+  r = cfs_write(fd, &record, sizeof(record));
+  if(r != sizeof(record)) {
+    printf("failed to write %d bytes to %s\n",
+           (int)sizeof(record), FILENAME);
+    cfs_close(fd);
+    return 0;
+  }
+
+  printf("Wrote message \"%s\", sequence %u\n",
+         record.message, record.sequence);
+
+  /* To read back the message, we need to move the file pointer to the 
+     beginning of the file. */
+  if(cfs_seek(fd, 0, CFS_SEEK_SET) != 0) {
+    printf("seek failed\n");
+    cfs_close(fd);
+    return 0;
+  }
+
+  /* Read all written records and print their contents. */
+  for(;;) {
+    r = cfs_read(fd, &record, sizeof(record));
+    if(r == 0) {
+      break;
+    } else if(r < sizeof(record)) {
+      printf("failed to read %d bytes from %s, got %d\n",
+             (int)sizeof(record), FILENAME, r);
+      cfs_close(fd);
+      return 0;
+    }
+
+    printf("Read message \"%s\", sequence %u\n",
+           record.message, record.sequence);
+  }
+
+  /* Release the internal resources held by Coffee for
+     the file descriptor. */
+  cfs_close(fd);
+
+  return 1;
+}
+
+static int
+dir_test(void)
+{
+  struct cfs_dir dir;
+  struct cfs_dirent dirent;
+
+  /* Coffee provides a root directory only. */
+  if(cfs_opendir(&dir, "/") != 0) {
+    printf("failed to open the root directory\n");
+    return 0;
+  }
+
+  /* List all files and their file sizes. */
+  printf("Available files\n");
+  while(cfs_readdir(&dir, &dirent) == 0) {
+    printf("%s (%lu bytes)\n", dirent.name, (unsigned long)dirent.size);
+  }
+
+  cfs_closedir(&dir);
+
+  return 1;
+}
+
+PROCESS_THREAD(example_coffee_process, ev, data)
+{
+  PROCESS_BEGIN();
+
+#if NEED_FORMATTING
+  cfs_coffee_format();
+#endif
+
+  /* Ensure that we will be working with a new file. */
+  cfs_remove(FILENAME);
+
+  if(file_test(FILENAME, "The first test") == 0) {
+    printf("file test 1 failed\n");
+  }
+  if(file_test(FILENAME, "The second test") == 0) {
+    printf("file test 2 failed\n");
+  }
+  if(dir_test() == 0) {
+    printf("dir test failed\n");
+  }
+
+  PROCESS_END();
+}