public static Session Load (FileSystemDatabase fsd, int key)
{
var toLoad = fsd.Read (key);
if (toLoad == null) {
return null;
}
var result = new Session ();
result.Id = key;
if (toLoad.ContainsKey (ShovelVmStateName)) {
result.ShovelVmState = toLoad [ShovelVmStateName];
}
if (toLoad.ContainsKey (ShovelVmBytecodeName)) {
result.ShovelVmBytecode = toLoad [ShovelVmBytecodeName];
}
if (toLoad.ContainsKey (ShovelVmSourcesName)) {
result.ShovelVmSources = Encoding.UTF8.GetString (toLoad [ShovelVmSourcesName]);
}
if (toLoad.ContainsKey (PageContentName)) {
result.PageContent.Append (Encoding.UTF8.GetString (toLoad [PageContentName]));
}
if (toLoad.ContainsKey (ReadStateName)) {
result.ReadState = (ReadStates)BitConverter.ToInt32 (toLoad [ReadStateName], 0);
}
return result;
}
static Session FreshSession(FileSystemDatabase fsd, Shovel.Instruction[] bytecode, string program)
{
var session = new Session ();
session.Id = fsd.GetFreshId ();
session.ShovelVmSources = program;
session.ShovelVmBytecode = Shovel.Api.SerializeBytecode (bytecode);
return session;
}
static IEnumerable<Shovel.Callable> Udps(Session session, string userInput)
{
var rng = new Random ();
Action<Shovel.VmApi, Shovel.Value[], Shovel.UdpResult> print = (api, args, result) =>
{
if (args.Length > 0 && args [0].Kind == Shovel.Value.Kinds.String) {
session.PageContent.Append ("<span>");
session.PageContent.Append (HttpUtility.HtmlEncode (args [0].StringValue));
session.PageContent.Append ("</span>");
} else {
session.PageContent.Append ("PRINT call failed!");
}
};
Action<Shovel.VmApi, Shovel.Value[], Shovel.UdpResult> printLn = (api, args, result) =>
{
if (args.Length > 0 && args [0].Kind == Shovel.Value.Kinds.String) {
session.PageContent.Append ("<span>");
session.PageContent.Append (HttpUtility.HtmlEncode (args [0].StringValue));
session.PageContent.Append ("</span><br/>");
} else {
session.PageContent.Append ("PRINT call failed!");
}
};
Action<Shovel.VmApi, Shovel.Value[], Shovel.UdpResult> readLine = (api, args, result) =>
{
if (session.ReadState == Session.ReadStates.None) {
result.After = Shovel.UdpResult.AfterCall.NapAndRetryOnWakeUp;
session.ReadState = Session.ReadStates.ReadLine;
} else if (session.ReadState == Session.ReadStates.ReadLine) {
result.Result = Shovel.Value.Make (userInput);
session.ReadState = Session.ReadStates.None;
session.PageContent.Append (HttpUtility.HtmlEncode (userInput));
session.PageContent.Append ("<br/>");
} else {
throw new InvalidOperationException ();
}
};
Action<Shovel.VmApi, Shovel.Value[], Shovel.UdpResult> readInt = (api, args, result) =>
{
if (session.ReadState == Session.ReadStates.None) {
result.After = Shovel.UdpResult.AfterCall.NapAndRetryOnWakeUp;
session.ReadState = Session.ReadStates.ReadInteger;
} else if (session.ReadState == Session.ReadStates.ReadInteger) {
int dummy;
if (!int.TryParse (userInput, out dummy)) {
dummy = 0;
}
result.Result = Shovel.Value.MakeInt (dummy);
session.ReadState = Session.ReadStates.None;
session.PageContent.Append (HttpUtility.HtmlEncode (userInput));
session.PageContent.Append ("<br/>");
} else {
throw new InvalidOperationException ();
}
};
Action<Shovel.VmApi, Shovel.Value[], Shovel.UdpResult> readChar = (api, args, result) =>
{
if (session.ReadState == Session.ReadStates.None) {
result.After = Shovel.UdpResult.AfterCall.NapAndRetryOnWakeUp;
session.ReadState = Session.ReadStates.ReadChar;
} else if (session.ReadState == Session.ReadStates.ReadChar) {
var line = userInput;
if (line.Length > 0) {
result.Result = Shovel.Value.Make (line.Substring (0, 1));
} else {
result.Result = Shovel.Value.Make ("");
}
session.ReadState = Session.ReadStates.None;
session.PageContent.Append (HttpUtility.HtmlEncode (userInput));
session.PageContent.Append ("<br/>");
} else {
throw new InvalidOperationException ();
}
};
Action<Shovel.VmApi, Shovel.Value[], Shovel.UdpResult> random = (api, args, result) =>
{
result.Result = Shovel.Value.MakeFloat (rng.NextDouble ());
};
return new Shovel.Callable[] {
Shovel.Callable.MakeUdp ("print", print, 1),
Shovel.Callable.MakeUdp ("printLn", printLn, 1),
Shovel.Callable.MakeUdp ("readLine", readLine, 0),
Shovel.Callable.MakeUdp ("readInt", readInt, 0),
Shovel.Callable.MakeUdp ("readChar", readChar, 0),
Shovel.Callable.MakeUdp ("random", random, 0),
};
}
static void ServeSession(HttpListenerContext ctx, FileSystemDatabase fsd, Session session, string userInput)
{
var vm = Shovel.Api.RunVm (
Shovel.Api.DeserializeBytecode (session.ShovelVmBytecode),
ProgramSources (session.ShovelVmSources),
Udps (session, userInput),
session.ShovelVmState,
totalTicksQuota: null,
ticksUntilNextNapQuota: null,
usedCellsQuota: null);
if (Shovel.Api.VmProgrammingError (vm) != null) {
ServeError (ctx, session, Shovel.Api.VmProgrammingError (vm).Message);
} else if (Shovel.Api.VmUserDefinedPrimitiveError (vm) != null) {
ServeError (ctx, session, Shovel.Api.VmUserDefinedPrimitiveError (vm).Message);
} else if (Shovel.Api.VmExecutionComplete (vm)) {
using (var sw = new StreamWriter(ctx.Response.OutputStream)) {
sw.Write ("<!DOCTYPE html>\n");
sw.Write (session.PageContent.ToString ());
sw.Write ("<p>Program execution completed.</p>");
sw.Write ("<a href='/' id='restart-link'>Enter another program.</p>");
sw.Write ("<script>\n");
sw.Write ("document.getElementById('restart-link').focus()\n");
sw.Write ("</script>\n");
}
} else {
session.ShovelVmState = Shovel.Api.SerializeVmState (vm);
session.Id = fsd.GetFreshId ();
session.Save (fsd);
using (var sw = new StreamWriter(ctx.Response.OutputStream)) {
sw.Write ("<!DOCTYPE html>\n");
sw.Write (session.PageContent.ToString ());
sw.Write ("<form action='/' method='get'>");
sw.Write ("<input type='text' name='input' id='shovel-input'/>");
sw.Write ("<input type='submit' value='Submit'/>");
sw.Write (String.Format (
"<input type='hidden' name='sessionid' value='{0}' id='shovel-input'/>",
session.Id)
);
sw.Write ("</form>");
sw.Write ("<script>\n");
sw.Write ("document.getElementById('shovel-input').focus()\n");
sw.Write ("</script>\n");
}
}
ctx.Response.OutputStream.Close ();
}
static void ServeError(HttpListenerContext ctx, Session session, string error)
{
using (var sw = new StreamWriter(ctx.Response.OutputStream)) {
sw.Write ("<!DOCTYPE html>\n");
sw.Write (session.PageContent.ToString ());
sw.Write ("<p>Program execution failed.</p>");
sw.Write ("<pre>");
sw.Write (HttpUtility.HtmlEncode (error));
sw.Write ("</pre>");
sw.Write ("<a href='/' id='restart-link'>Enter another program.</p>");
sw.Write ("<script>\n");
sw.Write ("document.getElementById('restart-link').focus()\n");
sw.Write ("</script>\n");
}
}