Add print_info.c example & fix deserialization

examples/leave_comment.c

@@ -1,5 +1,4 @@
 /* Reads text from stdio and creates comment using unix fs driver in current directory */
-/* TODO: add path, displayname as arguments */
 
 #include <stdio.h>
 #include <time.h>
@@ -24,9 +23,11 @@ get_username()
     return "";
 }
 
-void usage() {
+void
+usage()
+{
     fprintf(stderr, "Simple utility to leave comment using unix_fs_driver\n");
-    fprintf(stderr, "usage: <tool-name> [-p path] [-r reply_id] [-d displayname] [-i input_file]");
+    fprintf(stderr, "usage: <tool-name> [-p path] [-r reply_id] [-d displayname] [-i input_file]\n");
     fprintf(stderr, "-p path:\t path to comment storage \n");
     fprintf(stderr, "-r reply_id:\t ID of comment you are replying to, 0 if yours is top-level\n");
     fprintf(stderr, "-d displayname:\t Displayname to attach to comment\n");

examples/print_info.c

@@ -0,0 +1,83 @@
+/* Simple utility to get human-readable comment data */
+
+#include <stdio.h>
+#include <time.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "comment.h"
+#include "driver.h"
+#include "drivers/unix_fs/unix_fs_driver.h"
+
+#define BUF_SZ 4096
+
+void
+usage()
+{
+    fprintf(stderr, "Simple utility to get comment info\n");
+    fprintf(stderr, "usage: <tool-name> [-p path] id\n");
+    fprintf(stderr, "-p path: path to comment storage \n");
+    fprintf(stderr, "id     : id of comment \n");
+}
+
+int
+main(int argc, char *argv[])
+{
+    const Driver *driver = &unix_fs_driver;
+    char *path = ".";
+
+    int id, opt;
+
+    while ((opt = getopt(argc, argv, "p:")) != -1) {
+        switch (opt) {
+            case 'p':
+                path = optarg;
+                break;
+            default:
+                usage();
+                exit(EXIT_FAILURE);
+        }
+    }
+
+    if (optind >= argc) {
+        usage();
+        exit(EXIT_FAILURE);
+    }
+
+    id = atoi(argv[optind]);
+
+    if (id <= 0) {
+        usage();
+        exit(EXIT_FAILURE);
+    }
+
+    CommentHeader *header = malloc(sizeof(CommentHeader));
+    header->user_sid = malloc(BUF_SZ);
+    header->user_displayname = malloc(BUF_SZ);
+
+    UnixFsDriverData driver_data = { path };
+
+    if (driver->get_header(&driver_data, header, id) < 0) {
+        fprintf(stderr, "failed to get header of comment, are you sure it exists?\n");
+        exit(EXIT_FAILURE);
+    }
+
+    printf("Got a valid comment header\n");
+    printf("%-30s: %d\n", "Reply id", header->reply_id);
+    struct tm tm = *localtime(&header->creation_time);
+    printf("%-30s: %d-%02d-%02d %02d:%02d:%02d\n", "Creation time", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
+    printf("%-30s: %lu\n", "Text size in bytes", header->text_length);
+    printf("%-30s: %s\n", "User string ID", header->user_sid);
+    printf("%-30s: %s\n", "User displayname", header->user_displayname);
+
+    char *text_buffer = malloc(header->text_length + 1);
+    if (driver->get_text(&driver_data, text_buffer, id) < 0) {
+        fprintf(stderr, "failed to get text of comment\n");
+        exit(EXIT_FAILURE);
+    }
+
+    printf("Comment text:\n");
+    printf(text_buffer);
+}

src/drivers/unix_fs/unix_fs_driver.c

@@ -46,6 +46,8 @@ deserialize_header(int fd, CommentHeader *header)
     int bytes_read;
     size_t len, dst_idx, i;
 
+    i = 0;
+
     dst_bufs[0] = header->user_sid;
     dst_bufs[1] = header->user_displayname;
     dst_idx = 0;
@@ -56,9 +58,8 @@ deserialize_header(int fd, CommentHeader *header)
 
     while ((bytes_read = read(fd, buf, READ_BUF_SZ))) {
         for (; i < bytes_read; ++i) {
-            if (buf[i] != '\0') {
             *(dst_bufs[dst_idx]++) = buf[i];
-            } else {
+            if (buf[i] == '\0') {
                 dst_idx++;
             }
         }