Merge pull request #402 from martindevans/safer_model_handle_creation

Safer Model Handle Creation

LLama/Native/NativeApi.cs

@@ -71,15 +71,13 @@ public static partial class NativeApi
         public static extern bool llama_mlock_supported();
 
         /// <summary>
-        /// Various functions for loading a ggml llama model.
-        /// Allocate (almost) all memory needed for the model.
-        /// Return NULL on failure
+        /// Load all of the weights of a model into memory.
         /// </summary>
         /// <param name="path_model"></param>
         /// <param name="params"></param>
-        /// <returns></returns>
+        /// <returns>The loaded model, or null on failure.</returns>
         [DllImport(libraryName, CallingConvention = CallingConvention.Cdecl)]
-        public static extern IntPtr llama_load_model_from_file(string path_model, LLamaModelParams @params);
+        public static extern SafeLlamaModelHandle llama_load_model_from_file(string path_model, LLamaModelParams @params);
 
         /// <summary>
         /// Create a new llama_context with the given model.
@@ -92,12 +90,11 @@ public static partial class NativeApi
         public static extern IntPtr llama_new_context_with_model(SafeLlamaModelHandle model, LLamaContextParams @params);
 
         /// <summary>
-        /// not great API - very likely to change. 
         /// Initialize the llama + ggml backend
         /// Call once at the start of the program
         /// </summary>
         [DllImport(libraryName, CallingConvention = CallingConvention.Cdecl)]
-        public static extern void llama_backend_init(bool numa);
+        private static extern void llama_backend_init(bool numa);
 
         /// <summary>
         /// Frees all allocated memory in the given llama_context
@@ -510,10 +507,20 @@ public static int llama_model_meta_val_str_by_index(SafeLlamaModelHandle model,
         /// <param name="model"></param>
         /// <param name="llamaToken"></param>
         /// <param name="buffer">buffer to write string into</param>
-        /// <param name="length">size of the buffer</param>
         /// <returns>The length written, or if the buffer is too small a negative that indicates the length required</returns>
-        [DllImport(libraryName, CallingConvention = CallingConvention.Cdecl)]
-        public static extern unsafe int llama_token_to_piece(SafeLlamaModelHandle model, int llamaToken, byte* buffer, int length);
+        public static int llama_token_to_piece(SafeLlamaModelHandle model, llama_token llamaToken, Span<byte> buffer)
+        {
+            unsafe
+            {
+                fixed (byte* bufferPtr = buffer)
+                {
+                    return llama_token_to_piece_native(model, llamaToken, bufferPtr, buffer.Length);
+                }
+            }
+
+            [DllImport(libraryName, CallingConvention = CallingConvention.Cdecl, EntryPoint = "llama_token_to_piece")]
+            static extern unsafe int llama_token_to_piece_native(SafeLlamaModelHandle model, llama_token llamaToken, byte* buffer, int length);
+        }
 
         /// <summary>
         /// Convert text into tokens

LLama/Native/SafeLlamaModelHandle.cs

@@ -16,44 +16,33 @@ public sealed class SafeLlamaModelHandle
         /// <summary>
         /// Total number of tokens in vocabulary of this model
         /// </summary>
-        public int VocabCount { get; }
+        public int VocabCount => NativeApi.llama_n_vocab(this);
 
         /// <summary>
         /// Total number of tokens in the context
         /// </summary>
-        public int ContextSize { get; }
+        public int ContextSize => NativeApi.llama_n_ctx_train(this);
 
         /// <summary>
         /// Dimension of embedding vectors
         /// </summary>
-        public int EmbeddingSize { get; }
+        public int EmbeddingSize => NativeApi.llama_n_embd(this);
 
         /// <summary>
         /// Get the size of this model in bytes
         /// </summary>
-        public ulong SizeInBytes { get; }
+        public ulong SizeInBytes => NativeApi.llama_model_size(this);
 
         /// <summary>
         /// Get the number of parameters in this model
         /// </summary>
-        public ulong ParameterCount { get; }
+        public ulong ParameterCount => NativeApi.llama_model_n_params(this);
 
         /// <summary>
         /// Get the number of metadata key/value pairs
         /// </summary>
         /// <returns></returns>
-        public int MetadataCount { get; }
-
-        internal SafeLlamaModelHandle(IntPtr handle)
-            : base(handle)
-        {
-            VocabCount = NativeApi.llama_n_vocab(this);
-            ContextSize = NativeApi.llama_n_ctx_train(this);
-            EmbeddingSize = NativeApi.llama_n_embd(this);
-            SizeInBytes = NativeApi.llama_model_size(this);
-            ParameterCount = NativeApi.llama_model_n_params(this);
-            MetadataCount = NativeApi.llama_model_meta_count(this);
-        }
+        public int MetadataCount => NativeApi.llama_model_meta_count(this);
 
         /// <inheritdoc />
         protected override bool ReleaseHandle()
@@ -73,10 +62,10 @@ protected override bool ReleaseHandle()
         public static SafeLlamaModelHandle LoadFromFile(string modelPath, LLamaModelParams lparams)
         {
             var model_ptr = NativeApi.llama_load_model_from_file(modelPath, lparams);
-            if (model_ptr == IntPtr.Zero)
+            if (model_ptr == null)
                 throw new RuntimeError($"Failed to load model {modelPath}.");
 
-            return new SafeLlamaModelHandle(model_ptr);
+            return model_ptr;
         }
 
         #region LoRA
@@ -114,14 +103,8 @@ public void ApplyLoraFromFile(string lora, float scale, string? modelBase = null
         /// <returns>The size of this token. **nothing will be written** if this is larger than `dest`</returns>
         public int TokenToSpan(int llama_token, Span<byte> dest)
         {
-            unsafe
-            {
-                fixed (byte* destPtr = dest)
-                {
-                    var length = NativeApi.llama_token_to_piece(this, llama_token, destPtr, dest.Length);
-                    return Math.Abs(length);
-                }
-            }
+            var length = NativeApi.llama_token_to_piece(this, llama_token, dest);
+            return Math.Abs(length);
         }
 
         /// <summary>