Class: Jlog::Reader

Inherits:
Jlog
  • Object
show all
Defined in:
ext/jlog/jlog.c

Constant Summary

Constants inherited from Jlog

VERSION

Instance Method Summary collapse

Methods inherited from Jlog

#add_subscriber, #close, #destroy, #inspect, #list_subscribers, #raw_size, #remove_subscriber

Constructor Details

#initialize(*args) ⇒ Object 



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# File 'ext/jlog/jlog.c', line 58

VALUE rJlog_initialize(int argc, VALUE* argv, VALUE klass) 
{
   int options;
   Jlog jo;
   jlog_id zeroed = {0,0};
   VALUE path;
   VALUE optarg;
   VALUE size;

   rb_scan_args(argc, argv, "12", &path, &optarg, &size);

   if(NIL_P(optarg)) {
      options = O_CREAT;
   } else {
      options = (int)NUM2INT(optarg);
   }

   if(NIL_P(size)) {
      size = (size_t)INT2FIX(0);
   }

   Data_Get_Struct(klass, jlog_obj, jo);

   jo->ctx = jlog_new(StringValuePtr(path));
   jo->path = strdup(StringValuePtr(path));
   jo->auto_checkpoint = 0;
   jo->start = zeroed;
   jo->prev = zeroed;
   jo->last = zeroed;
   jo->end = zeroed;


   if(!jo->ctx) {
      rJlog_free(jo);
      rb_raise(eJlog, "jlog_new(%s) failed", StringValuePtr(path));
   }

   if(options & O_CREAT) {
      if(jlog_ctx_init(jo->ctx) != 0) {
         if(jlog_ctx_err(jo->ctx) == JLOG_ERR_CREATE_EXISTS) {
            if(options & O_EXCL) {
               rJlog_free(jo);
               rb_raise(eJlog, "file already exists: %s", StringValuePtr(path));
            }
         }else {
            rJlog_raise(jo, "Error initializing jlog");
         }
      }
      jlog_ctx_close(jo->ctx);
      jo->ctx = jlog_new(StringValuePtr(path));
      if(!jo->ctx) {
         rJlog_free(jo);
         rb_raise(eJlog, "jlog_new(%s) failed after successful init", StringValuePtr(path));
      }
      rJlog_populate_subscribers(klass);
   } 

   if(!jo) { 
      rb_raise(eJlog, "jo wasn't initialized.");
   }

   return klass;
}

Instance Method Details

#auto_checkpoint(*args) ⇒ Object 



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# File 'ext/jlog/jlog.c', line 533

VALUE rJlog_R_auto_checkpoint(int argc, VALUE *argv, VALUE self)
{
   Jlog jo;

   Data_Get_Struct(self, jlog_obj, jo);

   if(!jo || !jo->ctx) {
      rb_raise(eJlog, "Invalid jlog context");
   }

   if(argc > 0) {
      int ac = FIX2INT(argv[0]);
      jo->auto_checkpoint = ac;
   }

   return INT2FIX(jo->auto_checkpoint);
}

#checkpoint ⇒ Object 



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# File 'ext/jlog/jlog.c', line 508

VALUE rJlog_R_checkpoint(VALUE self)
{
   jlog_id epoch = { 0, 0 };
   Jlog_Reader jo;

   Data_Get_Struct(self, jlog_obj, jo);

   if(!jo || !jo->ctx) {
      rb_raise(eJlog, "Invalid jlog context");
   }

   if(memcmp(&jo->last, &epoch, sizeof(jlog_id)))
   {
      jlog_ctx_read_checkpoint(jo->ctx, &jo->last);

      // re-read the interval
      jo->last = epoch;
      jo->start = epoch;
      jo->end = epoch;
   }

   return Qtrue;
}

#open(subscriber) ⇒ Object 



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# File 'ext/jlog/jlog.c', line 307

VALUE rJlog_R_open(VALUE self, VALUE subscriber)
{
   Jlog_Reader jo;
   int err;

   Data_Get_Struct(self, jlog_obj, jo);

   if(!jo || !jo->ctx) {
      rb_raise(eJlog, "Invalid jlog context");
   }

   err = jlog_ctx_open_reader(jo->ctx, StringValuePtr(subscriber));

   if(err != 0) {
      rJlog_raise(jo, "jlog_ctx_open_reader failed");
   }

   return Qtrue;
}

#read ⇒ Object 



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# File 'ext/jlog/jlog.c', line 328

VALUE rJlog_R_read(VALUE self)
{
   const jlog_id epoch = {0, 0};
   jlog_id cur = {0, 0};
   jlog_message message;
   int cnt;
   Jlog_Reader jo;

   Data_Get_Struct(self, jlog_obj, jo);

   if(!jo || !jo->ctx) {
      rb_raise(eJlog, "Invalid jlog context");
   }

   // If start is unset, read the interval
   if(jo->error || !memcmp(&jo->start, &epoch, sizeof(jlog_id)))
   {
      jo->error = 0;
      cnt = jlog_ctx_read_interval(jo->ctx, &jo->start, &jo->end);
      if(cnt == 0 || (cnt == -1 && jlog_ctx_err(jo->ctx) == JLOG_ERR_FILE_OPEN)) {
         jo->start = epoch;
         jo->end = epoch;
         return Qnil;
      }
      else if(cnt == -1)
         rJlog_raise(jo, "jlog_ctx_read_interval_failed");
   }

   // If last is unset, start at the beginning
   if(!memcmp(&jo->last, &epoch, sizeof(jlog_id))) {
      cur = jo->start;
   } else {
      // if we've already read the end, return; otherwise advance
      cur = jo->last;
      if(!memcmp(&jo->prev, &jo->end, sizeof(jlog_id))) {
         jo->start = epoch;
         jo->end = epoch;
         return Qnil;
      }
      jlog_ctx_advance_id(jo->ctx, &jo->last, &cur, &jo->end);
      if(!memcmp(&jo->last, &cur, sizeof(jlog_id))) {
            jo->start = epoch;
            jo->end = epoch;
            return Qnil;
      }
   }

   if(jlog_ctx_read_message(jo->ctx, &cur, &message) != 0) {
      if(jlog_ctx_err(jo->ctx) == JLOG_ERR_FILE_OPEN) {
         jo->error = 1;
         rJlog_raise(jo, "jlog_ctx_read_message failed");
         return Qnil;
      }

      // read failed; raise error but recover if read is retried
      jo->error = 1;
      rJlog_raise(jo, "read failed");
   }

   if(jo->auto_checkpoint) {
      if(jlog_ctx_read_checkpoint(jo->ctx, &cur) != 0)
         rJlog_raise(jo, "checkpoint failed");

      // must reread the interval after a checkpoint
      jo->last = epoch;
      jo->prev = epoch;
      jo->start = epoch;
      jo->end = epoch;
   } else {
      // update last
      jo->prev = jo->last;
      jo->last = cur;
   }

   return rb_str_new2(message.mess);
}

#read_message ⇒ Object 



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# File 'ext/jlog/jlog.c', line 405

VALUE rJlog_R_read_message(VALUE self)
{
   const jlog_id epoch = {0, 0};
   jlog_id cur = {0, 0};
   jlog_message message;
   int cnt;
   double ts;
   Jlog_Reader jo;
   VALUE message_hash;

   Data_Get_Struct(self, jlog_obj, jo);

   if(!jo || !jo->ctx) {
      rb_raise(eJlog, "Invalid jlog context");
   }

   // If start is unset, read the interval
   if(jo->error || !memcmp(&jo->start, &epoch, sizeof(jlog_id)))
   {
      jo->error = 0;
      cnt = jlog_ctx_read_interval(jo->ctx, &jo->start, &jo->end);
      if(cnt == 0 || (cnt == -1 && jlog_ctx_err(jo->ctx) == JLOG_ERR_FILE_OPEN)) {
         jo->start = epoch;
         jo->end = epoch;
         return Qnil;
      }
      else if(cnt == -1)
         rJlog_raise(jo, "jlog_ctx_read_interval_failed");
   }

   // If last is unset, start at the beginning
   if(!memcmp(&jo->last, &epoch, sizeof(jlog_id))) {
      cur = jo->start;
   } else {
      // if we've already read the end, return; otherwise advance
      cur = jo->last;
      if(!memcmp(&jo->prev, &jo->end, sizeof(jlog_id))) {
         jo->start = epoch;
         jo->end = epoch;
         return Qnil;
      }
      jlog_ctx_advance_id(jo->ctx, &jo->last, &cur, &jo->end);
      if(!memcmp(&jo->last, &cur, sizeof(jlog_id))) {
            jo->start = epoch;
            jo->end = epoch;
            return Qnil;
      }
   }

   if(jlog_ctx_read_message(jo->ctx, &cur, &message) != 0) {
      if(jlog_ctx_err(jo->ctx) == JLOG_ERR_FILE_OPEN) {
         jo->error = 1;
         rJlog_raise(jo, "jlog_ctx_read_message failed");
         return Qnil;
      }

      // read failed; raise error but recover if read is retried
      jo->error = 1;
      rJlog_raise(jo, "read failed");
   }

   if(jo->auto_checkpoint) {
      if(jlog_ctx_read_checkpoint(jo->ctx, &cur) != 0)
         rJlog_raise(jo, "checkpoint failed");

      // must reread the interval after a checkpoint
      jo->last = epoch;
      jo->prev = epoch;
      jo->start = epoch;
      jo->end = epoch;
   } else {
      // update last
      jo->prev = jo->last;
      jo->last = cur;
   }

   ts = message.header->tv_sec+(message.header->tv_usec/1000000.0);

   message_hash = rb_hash_new();
   rb_hash_aset(message_hash, message_sym, rb_str_new2(message.mess));
   rb_hash_aset(message_hash, timestamp_sym, rb_float_new(ts));

   
   return message_hash;
}

#rewind ⇒ Object 



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# File 'ext/jlog/jlog.c', line 492

VALUE rJlog_R_rewind(VALUE self)
{
   Jlog_Reader jo;

   Data_Get_Struct(self, jlog_obj, jo);

   if(!jo || !jo->ctx) {
      rb_raise(eJlog, "Invalid jlog context");
   }

   jo->last = jo->prev;

   return Qtrue;
}