feat: add Linker class

4 files changed, 80 insertions, 21 deletions

diff --git a/src/WebAssembly/Execution/ExporterInterface.php b/src/WebAssembly/Execution/ExporterInterface.php
new file mode 100644
index 0000000..9c2d965
--- /dev/null
+++ b/src/WebAssembly/Execution/ExporterInterface.php
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nsfisis\Waddiwasi\WebAssembly\Execution;
+
+interface ExporterInterface
+{
+    /**
+     * @return list<ExportInst>
+     */
+    public function exports(): array;
+}
diff --git a/src/WebAssembly/Execution/LinkErrorException.php b/src/WebAssembly/Execution/LinkErrorException.php
new file mode 100644
index 0000000..35db57f
--- /dev/null
+++ b/src/WebAssembly/Execution/LinkErrorException.php
@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nsfisis\Waddiwasi\WebAssembly\Execution;
+
+use RuntimeException;
+
+final class LinkErrorException extends RuntimeException
+{
+}
diff --git a/src/WebAssembly/Execution/Linker.php b/src/WebAssembly/Execution/Linker.php
new file mode 100644
index 0000000..3c9c1d0
--- /dev/null
+++ b/src/WebAssembly/Execution/Linker.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nsfisis\Waddiwasi\WebAssembly\Execution;
+
+use Nsfisis\Waddiwasi\WebAssembly\Structure\Modules\Module;
+
+final class Linker
+{
+    /**
+     * @var array<string, array<string, ExternVal>>
+     */
+    private array $symbols = [];
+
+    public function __construct(
+        private Store $store,
+    ) {
+    }
+
+    public function register(string $namespace, string $name, Extern $extern): void
+    {
+        $externVal = $this->store->register($extern);
+        $this->symbols[$namespace][$name] = $externVal;
+    }
+
+    public function registerNamespace(string $namespace, ExporterInterface $exporter): void
+    {
+        foreach ($exporter->exports() as $export) {
+            $this->symbols[$namespace][$export->name] = $export->value;
+        }
+    }
+
+    /**
+     * @return list<ExternVal>
+     */
+    public function resolve(Module $module): array
+    {
+        $externVals = [];
+        foreach ($module->imports as $import) {
+            $externVal = $this->symbols[$import->module][$import->name] ?? null;
+            if ($externVal === null) {
+                throw new LinkErrorException("import not found: {$import->module}::{$import->name}");
+            }
+            $externVals[] = $externVal;
+        }
+        return $externVals;
+    }
+}
diff --git a/src/WebAssembly/Execution/Runtime.php b/src/WebAssembly/Execution/Runtime.php
index 07dc0d0..c4a78c8 100644
--- a/src/WebAssembly/Execution/Runtime.php
+++ b/src/WebAssembly/Execution/Runtime.php
@@ -39,7 +39,7 @@ use function sqrt;
 use function unpack;
 use const PHP_INT_MIN;
 
-final class Runtime
+final class Runtime implements ExporterInterface
 {
     /**
      * @var array<string, array{int, int}>
@@ -54,28 +54,9 @@ final class Runtime
     }
 
     /**
-     * @param array<string, array<string, Extern>> $imports
-     */
-    public static function instantiate(
-        Store $store,
-        Module $module,
-        array $imports,
-    ): self {
-        $externVals = [];
-        foreach ($module->imports as $import) {
-            $extern = $imports[$import->module][$import->name] ?? null;
-            if ($extern === null) {
-                throw new RuntimeException("instantiate: import not found: {$import->module}::{$import->name}");
-            }
-            $externVals[] = $store->register($extern);
-        }
-        return self::doInstantiate($store, $module, $externVals);
-    }
-
-    /**
      * @param list<ExternVal> $externVals
      */
-    private static function doInstantiate(
+    public static function instantiate(
         Store $store,
         Module $module,
         array $externVals,
@@ -159,6 +140,11 @@ final class Runtime
         return new self($store, $stack, $moduleInst);
     }
 
+    public function exports(): array
+    {
+        return $this->module->exports;
+    }
+
     public function getExport(string $name): ?ExternVal
     {
         foreach ($this->module->exports as $export) {