/// <summary>
/// Load an optional object from the repository directory.
/// Returns false iff no stream was found for the object, iff result is set to null.
/// Throws if loading fails for any other reason.
/// </summary>
public static bool LoadModelOrNull <TRes, TSig>(IHostEnvironment env, out TRes result, RepositoryReader rep, string dir, params object[] extra)
where TRes : class
{
Contracts.CheckValue(env, nameof(env));
env.CheckValue(rep, nameof(rep));
var ent = rep.OpenEntryOrNull(dir, ModelStreamName);
if (ent != null)
{
using (ent)
{
// Provide the repository, entry, and directory name to the loadable class ctor.
env.Assert(ent.Stream.Position == 0);
LoadModel <TRes, TSig>(env, out result, rep, ent, dir, extra);
return(true);
}
}
if ((ent = rep.OpenEntryOrNull(dir, NameBinary)) != null)
{
using (ent)
{
env.Assert(ent.Stream.Position == 0);
LoadModel <TRes, TSig>(env, out result, ent.Stream, extra);
return(true);
}
}
result = null;
return(false);
}
/// <summary>
/// Try to load from the given repository entry using the default loader(s) specified in the header.
/// Returns false iff the default loader(s) could not be bound to a compatible loadable class.
/// </summary>
private static bool TryLoadModel <TRes, TSig>(IHostEnvironment env, out TRes result, RepositoryReader rep, Repository.Entry ent, string dir, params object[] extra)
where TRes : class
{
Contracts.CheckValue(env, nameof(env));
env.CheckValue(rep, nameof(rep));
long fp = ent.Stream.Position;
using (var ctx = new ModelLoadContext(rep, ent, dir))
{
env.Assert(fp == ctx.FpMin);
if (ctx.TryLoadModelCore <TRes, TSig>(env, out result, extra))
{
return(true);
}
}
// TryLoadModelCore should rewind on failure.
Contracts.Assert(fp == ent.Stream.Position);
return(false);
}
/// <summary>
/// Load from the given repository entry using the default loader(s) specified in the header.
/// </summary>
public static void LoadModel <TRes, TSig>(IHostEnvironment env, out TRes result, RepositoryReader rep, Repository.Entry ent, string dir, params object[] extra)
where TRes : class
{
Contracts.CheckValue(env, nameof(env));
env.CheckValue(rep, nameof(rep));
if (!TryLoadModel <TRes, TSig>(env, out result, rep, ent, dir, extra))
{
throw env.ExceptDecode("Couldn't load model: '{0}'", dir);
}
}
/// <summary>
/// Load an object from the repository directory.
/// </summary>
public static void LoadModel <TRes, TSig>(IHostEnvironment env, out TRes result, RepositoryReader rep, string dir, params object[] extra)
where TRes : class
{
Contracts.CheckValue(env, nameof(env));
env.CheckValue(rep, nameof(rep));
if (!LoadModelOrNull <TRes, TSig>(env, out result, rep, dir, extra))
{
throw env.ExceptDecode("Corrupt model file");
}
env.AssertValue(result);
}