/// <summary>
/// Create a <see cref="ModelSaveContext"/> supporting saving to a repository, for implementors of <see cref="ICanSaveModel"/>.
/// </summary>
internal ModelSaveContext(RepositoryWriter rep, string dir, string name)
{
Contracts.CheckValue(rep, nameof(rep));
Repository = rep;
_ectx = rep.ExceptionContext;
_ectx.CheckValueOrNull(dir);
_ectx.CheckNonEmpty(name, nameof(name));
Directory = dir;
Strings = new NormStr.Pool();
_ent = rep.CreateEntry(dir, name);
try
{
Writer = new BinaryWriter(_ent.Stream, Encoding.UTF8, leaveOpen: true);
try
{
ModelHeader.BeginWrite(Writer, out FpMin, out Header);
}
catch
{
Writer.Dispose();
throw;
}
}
catch
{
_ent.Dispose();
throw;
}
}
/// <summary>
/// Create a <see cref="ModelSaveContext"/> supporting saving to a single-stream, for implementors of <see cref="ICanSaveInBinaryFormat"/>.
/// </summary>
internal ModelSaveContext(BinaryWriter writer, IExceptionContext ectx = null)
{
Contracts.AssertValueOrNull(ectx);
_ectx = ectx;
_ectx.CheckValue(writer, nameof(writer));
Repository = null;
Directory = null;
_ent = null;
Strings = new NormStr.Pool();
Writer = writer;
ModelHeader.BeginWrite(Writer, out FpMin, out Header);
}
/// <summary>
/// Create a ModelLoadContext supporting loading from a repository, for implementors of ICanSaveModel.
/// </summary>
internal ModelLoadContext(RepositoryReader rep, Repository.Entry ent, string dir)
{
Contracts.CheckValue(rep, nameof(rep));
Repository = rep;
_ectx = rep.ExceptionContext;
_ectx.CheckValue(ent, nameof(ent));
_ectx.CheckValueOrNull(dir);
Directory = dir;
Reader = new BinaryReader(ent.Stream, Encoding.UTF8, leaveOpen: true);
try
{
ModelHeader.BeginRead(out FpMin, out Header, out Strings, out LoaderAssemblyName, Reader);
}
catch
{
Reader.Dispose();
throw;
}
}
/// <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>
/// 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);
}
