From 2c9ca4a74d2264c001c096d0dd06f34c8fa10a61 Mon Sep 17 00:00:00 2001
From: Mark McCaskey <mark@wasmer.io>
Date: Mon, 30 Nov 2020 13:50:40 -0800
Subject: [PATCH] Add engine::export

---
 lib/engine/src/export.rs | 103 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 103 insertions(+)
 create mode 100644 lib/engine/src/export.rs

diff --git a/lib/engine/src/export.rs b/lib/engine/src/export.rs
new file mode 100644
index 00000000000..8f972c3f79f
--- /dev/null
+++ b/lib/engine/src/export.rs
@@ -0,0 +1,103 @@
+use wasmer_vm::{
+    ImportInitializerFuncPtr, VMExport, VMExportFunction, VMExportGlobal, VMExportMemory,
+    VMExportTable,
+};
+
+/// The value of an export passed from one instance to another.
+#[derive(Debug, Clone)]
+pub enum Export {
+    /// A function export value.
+    Function(ExportFunction),
+
+    /// A table export value.
+    Table(ExportTable),
+
+    /// A memory export value.
+    Memory(ExportMemory),
+
+    /// A global export value.
+    Global(ExportGlobal),
+}
+
+impl From<Export> for VMExport {
+    fn from(other: Export) -> Self {
+        match other {
+            Export::Function(ExportFunction { vm_function, .. }) => VMExport::Function(vm_function),
+            Export::Memory(ExportMemory { vm_memory }) => VMExport::Memory(vm_memory),
+            Export::Table(ExportTable { vm_table }) => VMExport::Table(vm_table),
+            Export::Global(ExportGlobal { vm_global }) => VMExport::Global(vm_global),
+        }
+    }
+}
+
+impl From<VMExport> for Export {
+    fn from(other: VMExport) -> Self {
+        match other {
+            VMExport::Function(vm_function) => Export::Function(ExportFunction {
+                vm_function,
+                import_init_function_ptr: None,
+            }),
+            VMExport::Memory(vm_memory) => Export::Memory(ExportMemory { vm_memory }),
+            VMExport::Table(vm_table) => Export::Table(ExportTable { vm_table }),
+            VMExport::Global(vm_global) => Export::Global(ExportGlobal { vm_global }),
+        }
+    }
+}
+
+/// A function export value with an extra function pointer to initialize
+/// host environments.
+#[derive(Debug, Clone, PartialEq)]
+pub struct ExportFunction {
+    /// The VM function, containing most of the data.
+    pub vm_function: VMExportFunction,
+    /// Function pointer to `WasmerEnv::init_with_instance(&mut self, instance: &Instance)`.
+    ///
+    /// This function is called to finish setting up the environment after
+    /// we create the `api::Instance`.
+    pub import_init_function_ptr: Option<ImportInitializerFuncPtr>,
+}
+
+impl From<ExportFunction> for Export {
+    fn from(func: ExportFunction) -> Self {
+        Self::Function(func)
+    }
+}
+
+/// A table export value.
+#[derive(Debug, Clone)]
+pub struct ExportTable {
+    /// The VM table, containing info about the table.
+    pub vm_table: VMExportTable,
+}
+
+impl From<ExportTable> for Export {
+    fn from(table: ExportTable) -> Self {
+        Self::Table(table)
+    }
+}
+
+/// A memory export value.
+#[derive(Debug, Clone)]
+pub struct ExportMemory {
+    /// The VM memory, containing info about the table.
+    pub vm_memory: VMExportMemory,
+}
+
+impl From<ExportMemory> for Export {
+    fn from(memory: ExportMemory) -> Self {
+        Self::Memory(memory)
+    }
+}
+
+/// A global export value.
+#[derive(Debug, Clone)]
+pub struct ExportGlobal {
+    /// The VM global, containing info about the global.
+    pub vm_global: VMExportGlobal,
+}
+
+impl From<ExportGlobal> for Export {
+    fn from(global: ExportGlobal) -> Self {
+        Self::Global(global)
+    }
+}