Add DNMD API to create a new metadata handle and implement IMetaDataDispenser::DefineScope

src/dnmd/entry.c

@@ -248,6 +248,89 @@ bool md_create_handle(void const* data, size_t data_len, mdhandle_t* handle)
     return true;
 }
 
+// Initialize the minimal set of tables required for a valid metadata image.
+// Every image must have a row in the Module table
+// for module identity information
+// and a row in the TypeDef table for the global type.
+static bool initialize_minimal_table_rows(mdcxt_t* cxt)
+{
+    mdcursor_t module_cursor;
+    if (!md_append_row(cxt, mdtid_Module, &module_cursor))
+        return false;
+
+    // Set the Generation to 0
+    uint32_t generation = 0;
+    if (1 != md_set_column_value_as_constant(module_cursor, mdtModule_Generation, 1, &generation))
+        return false;
+
+    // Use the 0 index to specify the NULL guid as the guids for the image.
+    uint32_t guid_heap_offset = 0;
+    if (1 != set_column_value_as_heap_offset(module_cursor, mdtModule_Mvid, 1, &guid_heap_offset)
+        || 1 != set_column_value_as_heap_offset(module_cursor, mdtModule_EncBaseId, 1, &guid_heap_offset)
+        || 1 != set_column_value_as_heap_offset(module_cursor, mdtModule_EncId, 1, &guid_heap_offset))
+        return false;
+
+    const char* name = "";
+    if (1 != md_set_column_value_as_utf8(module_cursor, mdtModule_Name, 1, &name))
+        return false;
+
+    md_commit_row_add(module_cursor);
+
+    mdcursor_t global_type_cursor;
+    if (!md_append_row(cxt, mdtid_TypeDef, &global_type_cursor))
+        return false;
+
+    uint32_t flags = 0;
+    if (1 != md_set_column_value_as_constant(global_type_cursor, mdtTypeDef_Flags, 1, &flags))
+        return false;
+
+    const char* global_type_name = "<Module>";
+    if (1 != md_set_column_value_as_utf8(global_type_cursor, mdtTypeDef_TypeName, 1, &global_type_name))
+        return false;
+
+    char const* namespace = "";
+    if (1 != md_set_column_value_as_utf8(global_type_cursor, mdtTypeDef_TypeNamespace, 1, &namespace))
+        return false;
+
+    mdToken nil_typedef = CreateTokenType(mdtTypeDef);
+    if (1 != md_set_column_value_as_token(global_type_cursor, mdtTypeDef_Extends, 1, &nil_typedef))
+        return false;
+
+    md_commit_row_add(global_type_cursor);
+
+    return true;
+}
+
+mdhandle_t md_create_new_handle()
+{
+    mdcxt_t cxt;
+
+    memset(&cxt, 0, sizeof(mdcxt_t));
+    cxt.magic = MDLIB_MAGIC_NUMBER;
+    cxt.context_flags = mdc_none;
+    cxt.major_ver = 2;
+    cxt.minor_ver = 0;
+    cxt.flags = 0;
+    cxt.version = "v4.0.30319";
+    cxt.editor = NULL;
+    cxt.mem = NULL;
+
+    // Allocate and initialize a full context
+    // with the correctly-sized trailing memory.
+    mdcxt_t* pcxt = allocate_full_context(&cxt);
+    if (pcxt == NULL)
+        return NULL;
+
+    if (!initialize_minimal_table_rows(pcxt))
+    {
+        free(pcxt);
+        return NULL;
+    }
+
+    return pcxt;
+}
+
+
 bool md_apply_delta(mdhandle_t handle, void const* data, size_t data_len)
 {
     mdcxt_t* base = extract_mdcxt(handle);

src/inc/dnmd.h

@@ -38,6 +38,13 @@ typedef void* mdhandle_t;
 // If modifications are made, the data will not be updated in place.
 bool md_create_handle(void const* data, size_t data_len, mdhandle_t* handle);
 
+// Create a new metadata handle for a new image.
+// Returns a handle for the new image, or NULL if the handle could not be created.
+// The image will always be in the v2.0 metadata format,
+// use the "v4.0.30319" version string,
+// and have an MVID of all zeros.
+mdhandle_t md_create_new_handle();
+
 // Apply delta data to the current metadata.
 bool md_apply_delta(mdhandle_t handle, void const* data, size_t data_len);
 

src/interfaces/dispenser.cpp

@@ -24,11 +24,50 @@ namespace
             REFIID      riid,
             IUnknown** ppIUnk)
         {
-            UNREFERENCED_PARAMETER(rclsid);
-            UNREFERENCED_PARAMETER(dwCreateFlags);
-            UNREFERENCED_PARAMETER(riid);
-            UNREFERENCED_PARAMETER(ppIUnk);
-            return E_NOTIMPL;
+            if (rclsid != CLSID_CLR_v2_MetaData)
+            {
+                // DNMD::Interfaces only creating v2 metadata images.
+                return CLDB_E_FILE_OLDVER;
+            }
+
+            if (dwCreateFlags != 0)
+            {
+                return E_INVALIDARG;
+            }
+
+            mdhandle_ptr md_ptr { md_create_new_handle() };
+            if (md_ptr == nullptr)
+                return E_OUTOFMEMORY;
+
+            // Initialize the MVID of the new image.
+            mdcursor_t moduleCursor;
+            if (!md_token_to_cursor(md_ptr.get(), TokenFromRid(1, mdtModule), &moduleCursor))
+                return E_FAIL;
+
+            mdguid_t mvid;
+            HRESULT hr = PAL_CoCreateGuid(reinterpret_cast<GUID*>(&mvid));
+            if (FAILED(hr))
+                return hr;
+
+            if (1 != md_set_column_value_as_guid(moduleCursor, mdtModule_Mvid, 1, &mvid))
+                return E_OUTOFMEMORY;
+
+            dncp::com_ptr<ControllingIUnknown> obj;
+            obj.Attach(new (std::nothrow) ControllingIUnknown());
+            if (obj == nullptr)
+                return E_OUTOFMEMORY;
+
+            try
+            {
+                mdhandle_view handle_view{ obj->CreateAndAddTearOff<DNMDOwner>(std::move(md_ptr)) };
+                (void)obj->CreateAndAddTearOff<MetadataImportRO>(std::move(handle_view));
+            }
+            catch(std::bad_alloc const&)
+            {
+                return E_OUTOFMEMORY;
+            }
+
+            return obj->QueryInterface(riid, (void**)ppIUnk);
         }
 
         STDMETHOD(OpenScope)(

src/interfaces/dnmdowner.hpp

@@ -87,6 +87,13 @@ class DNMDOwner final : public TearOffBase<IDNMDOwner>
     }
 
 public:
+    DNMDOwner(IUnknown* controllingUnknown, mdhandle_ptr md_ptr)
+        : TearOffBase(controllingUnknown)
+        , _handle{ std::move(md_ptr) }
+        , _malloc_to_free{ nullptr }
+        , _cotaskmem_to_free{ nullptr }
+    { }
+
     DNMDOwner(IUnknown* controllingUnknown, mdhandle_ptr md_ptr, malloc_ptr<void> mallocMem, dncp::cotaskmem_ptr<void> cotaskmemMem)
         : TearOffBase(controllingUnknown)
         , _handle{ std::move(md_ptr) }

src/interfaces/iids.cpp

@@ -18,5 +18,8 @@ MIDL_DEFINE_GUID(IID_IMetaDataEmit2, 0xf5dd9950, 0xf693, 0x42e6, 0x83, 0xe, 0x7b
 // Define the ISymUnmanaged* IIDs here - corsym.h provides the declaration.
 MIDL_DEFINE_GUID(IID_ISymUnmanagedBinder, 0xaa544d42, 0x28cb, 0x11d3, 0xbd, 0x22, 0x00, 0x00, 0xf8, 0x08, 0x49, 0xbd);
 
+// Define option IIDs here - cor.h provides the declaration.
+MIDL_DEFINE_GUID(CLSID_CLR_v2_MetaData, 0xefea471a, 0x44fd, 0x4862, 0x92, 0x92, 0xc, 0x58, 0xd4, 0x6e, 0x1f, 0x3a);
+
 // Define an IID for our own marker interface
 MIDL_DEFINE_GUID(IID_IDNMDOwner, 0x250ebc02, 0x1a92, 0x4638, 0xaa, 0x6c, 0x3d, 0x0f, 0x98, 0xb3, 0xa6, 0xfb);