🦄 refactor: Revise snapshot native code

caoccao · Apr 17, 2024 · 5b3c583 · 5b3c583
1 parent f5699dc
commit 5b3c583
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Showing 5 changed files with 14 additions and 50 deletions.
diff --git a/cpp/jni/javet_jni_core_v8.cpp b/cpp/jni/javet_jni_core_v8.cpp
@@ -357,12 +357,7 @@ JNIEXPORT void JNICALL Java_com_caoccao_javet_interop_V8Native_setWeak
 
 JNIEXPORT jbyteArray JNICALL Java_com_caoccao_javet_interop_V8Native_snapshotCreate
 (JNIEnv* jniEnv, jobject caller, jlong v8RuntimeHandle) {
-#ifdef ENABLE_NODE
-    auto v8Runtime = Javet::V8Runtime::FromHandle(v8RuntimeHandle);
-    auto v8Locker = v8Runtime->GetSharedV8Locker();
-#else
     RUNTIME_HANDLES_TO_OBJECTS_WITH_SCOPE(v8RuntimeHandle);
-#endif
     return v8Runtime->CreateSnapshot(jniEnv);
 }
 

diff --git a/cpp/jni/javet_node.h b/cpp/jni/javet_node.h
@@ -31,7 +31,7 @@
 #include <env-inl.h>
 #include <crypto/crypto_util.h>
 #include <node_snapshot_builder.h>
-// Hack Begins (The hack is for resolving the conflicts between Node.js and V8)
+ // Hack Begins (The hack is for resolving the conflicts between Node.js and V8)
 #define BASE_TRACE_EVENT_COMMON_TRACE_EVENT_COMMON_H_
 #define V8_TRACING_TRACE_EVENT_H_
 #undef CHECK
@@ -72,5 +72,7 @@
 #endif
 
 constexpr auto DEFAULT_SCRIPT_NAME = "javet.js";
+constexpr auto INIT_SCRIPT_WITH_SNAPSHOT = "globalThis.require = require;";
+constexpr auto INIT_SCRIPT_WITHOUT_SNAPSHOT = "globalThis.require = require('module').createRequire(process.cwd() + '/');";
 
 #endif
diff --git a/cpp/jni/javet_v8.h b/cpp/jni/javet_v8.h
@@ -35,6 +35,7 @@
  // Scope
 
 using V8ContextScope = v8::Context::Scope;
+using V8EscapableHandleScope = v8::EscapableHandleScope;
 using V8HandleScope = v8::HandleScope;
 using V8IsolateScope = v8::Isolate::Scope;
 

diff --git a/cpp/jni/javet_v8_runtime.cpp b/cpp/jni/javet_v8_runtime.cpp
@@ -220,50 +220,18 @@ namespace Javet {
     jbyteArray V8Runtime::CreateSnapshot(JNIEnv* jniEnv) noexcept {
         jbyteArray jbytes = nullptr;
         if (v8SnapshotCreator) {
-#ifdef ENABLE_NODE
-            v8::MaybeLocal<v8::Context> v8MaybeLocalContext;
-            {
-                auto v8IsolateScope = GetV8IsolateScope();
-                V8HandleScope v8HandleScope(v8Isolate);
-                auto v8LocalContext = GetV8LocalContext();
-                auto v8ContextScope = GetV8ContextScope(v8LocalContext);
-                // Backup context and global object (Begin)
-                v8GlobalContext.Reset();
-                v8GlobalObject.Reset();
-                // Backup context and global object (End)
-                nodeIsolateData->Serialize(v8SnapshotCreator.get());
-                nodeEnvironment->Serialize(v8SnapshotCreator.get());
-                v8SnapshotCreator->SetDefaultContext(v8LocalContext, { node::SerializeNodeContextInternalFields, nodeEnvironment.get() });
-                v8MaybeLocalContext = v8::MaybeLocal<v8::Context>(v8LocalContext);
-            }
-            // TODO: Unknown external reference
-            v8::StartupData newV8StartupData = v8SnapshotCreator->CreateBlob(v8::SnapshotCreator::FunctionCodeHandling::kKeep);
-            if (newV8StartupData.IsValid()) {
-                jbytes = jniEnv->NewByteArray(newV8StartupData.raw_size);
-                jboolean isCopy;
-                void* data = jniEnv->GetPrimitiveArrayCritical(jbytes, &isCopy);
-                memcpy(data, newV8StartupData.data, newV8StartupData.raw_size);
-                jniEnv->ReleasePrimitiveArrayCritical(jbytes, data, JNI_ABORT);
-                delete[] newV8StartupData.data;
-            }
-            {
-                auto v8IsolateScope = GetV8IsolateScope();
-                V8HandleScope v8HandleScope(v8Isolate);
-                auto v8LocalContext = v8MaybeLocalContext.ToLocalChecked();
-                auto v8ContextScope = GetV8ContextScope(v8LocalContext);
-                // Restore context and global object (Begin)
-                v8GlobalContext.Reset(v8Isolate, v8LocalContext);
-                v8GlobalObject.Reset(
-                    v8Isolate, v8LocalContext->Global()->GetPrototype()->ToObject(v8LocalContext).ToLocalChecked());
-                // Restore context and global object (End)
-            }
-#else
             // Backup context and global object (Begin)
             auto v8LocalContext = GetV8LocalContext();
             v8GlobalContext.Reset();
             v8GlobalObject.Reset();
             // Backup context and global object (End)
+#ifdef ENABLE_NODE
+            nodeIsolateData->Serialize(v8SnapshotCreator.get());
+            nodeEnvironment->Serialize(v8SnapshotCreator.get());
+            v8SnapshotCreator->SetDefaultContext(v8LocalContext, { node::SerializeNodeContextInternalFields, nodeEnvironment.get() });
+#else
             v8SnapshotCreator->SetDefaultContext(v8LocalContext);
+#endif
             v8::StartupData newV8StartupData = v8SnapshotCreator->CreateBlob(v8::SnapshotCreator::FunctionCodeHandling::kKeep);
             if (newV8StartupData.IsValid()) {
                 jbytes = jniEnv->NewByteArray(newV8StartupData.raw_size);
@@ -278,7 +246,6 @@ namespace Javet {
             v8GlobalObject.Reset(
                 v8Isolate, v8LocalContext->Global()->GetPrototype()->ToObject(v8LocalContext).ToLocalChecked());
             // Restore context and global object (End)
-#endif
         }
         return jbytes;
     }
@@ -324,10 +291,10 @@ namespace Javet {
                 execArgs,
                 flags));
             // node::LoadEnvironment is thread-safe.
-            auto v8MaybeLocalValue = node::LoadEnvironment(
+            V8MaybeLocalValue v8MaybeLocalValue;
+            v8MaybeLocalValue = node::LoadEnvironment(
                 nodeEnvironment.get(),
-                "const publicRequire = require('module').createRequire(process.cwd() + '/');"
-                "globalThis.require = publicRequire;"
+                v8SnapshotCreator ? INIT_SCRIPT_WITH_SNAPSHOT : INIT_SCRIPT_WITHOUT_SNAPSHOT
             );
         }
 #else

diff --git a/docs/reference/resource_management/snapshot.rst b/docs/reference/resource_management/snapshot.rst
@@ -21,7 +21,7 @@ Benefits
 Limitations
 -----------
 
-* **Not all modules supported**: Only a subset of the built-in Node.js modules are currently supported in snapshots, so some applications might not be suitable for snapshotting.
+* **Node.js mode not supported**: Snapshot is only available in the V8 mode. There are some technical difficulties to be resolved in the Node.js mode.
 * **Dynamic code updates not possible**: Once a snapshot is created, it's static and cannot be updated with new code without creating a new snapshot.
 * **V8 version dependent**: The snapshot created from a particular version of V8 only works in that version of V8. If you want to support a new version of V8, you will have to create a new snapshot in that new version of V8.
 
@@ -87,7 +87,6 @@ It's simple to create a snapshot or provide an existing snapshot in Javet via th
 
 .. note:: 
 
-    * Snapshot is only available in the V8 mode. There are some technical difficulties to be resolved in the Node.js mode.
     * Both ``setCreateSnapshotEnabled()`` and ``setSnapshotBlob()`` can be used together so that you may create a V8 runtime by an existing snapshot, then create a new snapshot from that V8 runtime.
 
 Create a Snapshot via mksnapshot