Strange behaviour around fs.statSync

[espruino-discuss]

Posted at 2015-06-17 by JumJum

running this prints "..." on screen, so variable startAt is corrupted

function rtc2Date(dt){
  var t,d;
  d = dt.split(" ")[0]; t = dt.split(" ")[1];
  d = d.split("/"); t = t.split(":");
  return new Date(d[2] + 2000,d[1],d[0],t[0],t[1],t[2]);
}
var fs = require("fs");
var data = JSON.parse(fs.readFile("Juergen1_ctrl.json"));
var startAt = rtc2Date(data.options.startAt);
//console.log(startAt);
var entrys = fs.statSync("Juergen1_data.bin").size / 20;
console.log(startAt);

uncommented first console.log and it works fine:

function rtc2Date(dt){
  var t,d;
  d = dt.split(" ")[0]; t = dt.split(" ")[1];
  d = d.split("/"); t = t.split(":");
  return new Date(d[2] + 2000,d[1],d[0],t[0],t[1],t[2]);
}
var fs = require("fs");
var data = JSON.parse(fs.readFile("Juergen1_ctrl.json"));
var startAt = rtc2Date(data.options.startAt);
console.log(startAt);
var entrys = fs.statSync("Juergen1_data.bin").size / 20;
console.log(startAt);

Also had problems sometimes by using fs.statSync from terminal window. Connection to com-port was lost, and I had to reset and restart everything.
IMHO, this could be a problem around memory management for fs.statSync.
Using 1v80 on Espruino Board
Data returned from readFile is this:

{
  "tags": {
    "MQ2": "Methane, Butane, LPG, smoke",
    "MQ4": "Methane, CNG Gas",
    "MQ7": "Carbone Monoxide",
    "temp": "Temp",
    "rh": "Humidity"
   },
  "options": { "interval": 60000, "groupLength": 10,
    "startAt": "16/06/15 22:34:23"
   }
 }

[gfwilliams]

Posted at 2015-06-17 by @gfwilliams

Thanks - that looks interesting. I'll have a look and see if I can reproduce it.

I can't see anything immediately wrong in fs.statSync - it's possible it's actually an issue with Date.

[espruino-discuss]

Posted at 2015-06-17 by JumJum

Just tried to reproduce syncStat problem in a different way. Typed commands in terminal window:

• reset()
• require("fs").readdir()
• require("fs").syncStat("Juergen1_data.bin")
  There is no response from Espruino, so I
• closed connection
• clicked connect button and got an empty list, no COM port available anymore
• wrote these lines and about a minute later, a Com port is available
• tried to connect and got Connection failed
• unplugged Espruino Board from USB
• plugged Espruino Board
• now connect worked fine
• syncStat worked fine
  Hmmm, whats that ? So tried again:
• reset()
• require("fs").readdir()
• require("fs").statSync("Juergen1_data.bin")
• Espruino hangs again

[gfwilliams]

Posted at 2015-06-17 by @gfwilliams

What's in "Juergen1_data.bi­n"? I don't think you ever said.

I just tried this on an Espruino board with 1v79 from the website and it seems to work, so maybe my file Juergen1_data.bi­n is different somehow.

Having said that, I found that if readFile failed and sent undefined to JSON.parse it could cause you pretty major problems.

[gfwilliams]

Posted at 2015-06-17 by @gfwilliams

Nope, now it's breaking!

As you say, doing a readdir just before is enough to kill it. But readdir followed by a readFile is fine.

>require("fs").readFile("Juergen1_data.bin")
="Hello World"
>require("fs").statSync("Juergen1_data.bin")
={ "size": 11, "dir": false,
  "mtime": { "ms": 1328054400000 }
 }
>require("fs").readdir()
=[
  "Juergen.json",
  "Juergen1_ctrl.json",
  "Juerget1_data.bin",
  "Juergen1_data.bin",
  "Juerget1_data.bin~"
 ]
>require("fs").statSync("Juergen1_data.bin") 

Looks like this is something else dodgy in the SPI/Filesystem interface code :(