From 168d0ccdd7bdef2480a5e9e3fb3a36810795060c Mon Sep 17 00:00:00 2001
From: Tooru Fujisawa <arai_a@mac.com>
Date: Mon, 8 Jan 2024 14:57:37 +0000
Subject: [PATCH] Bug 1800641 - Part 4: Add
 ScriptLoadRequest::{Get,Set}SRILength. r=nbp

Depends on D197841

Differential Revision: https://phabricator.services.mozilla.com/D197842
---
 dom/script/ScriptLoadHandler.cpp |  6 +++---
 dom/script/ScriptLoader.cpp      | 19 ++++++++++++-------
 js/loader/ScriptLoadRequest.h    |  9 +++++++++
 3 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/dom/script/ScriptLoadHandler.cpp b/dom/script/ScriptLoadHandler.cpp
index 2840e97d7946..cff8eed5fd9e 100644
--- a/dom/script/ScriptLoadHandler.cpp
+++ b/dom/script/ScriptLoadHandler.cpp
@@ -187,7 +187,7 @@ ScriptLoadHandler::OnIncrementalData(nsIIncrementalStreamLoader* aLoader,
       return channelRequest->Cancel(mScriptLoader->RestartLoad(mRequest));
     }
     if (sriLength) {
-      mRequest->mBytecodeOffset = JS::AlignTranscodingBytecodeOffset(sriLength);
+      mRequest->SetSRILength(sriLength);
     }
   }
 
@@ -433,14 +433,14 @@ ScriptLoadHandler::OnStreamComplete(nsIIncrementalStreamLoader* aLoader,
         return channelRequest->Cancel(mScriptLoader->RestartLoad(mRequest));
       }
 
-      mRequest->mBytecodeOffset = JS::AlignTranscodingBytecodeOffset(sriLength);
+      mRequest->SetSRILength(sriLength);
 
       Vector<uint8_t> compressedBytecode;
       // mRequest has the compressed bytecode, but will be filled with the
       // uncompressed bytecode
       compressedBytecode.swap(bytecode);
       if (!JS::loader::ScriptBytecodeDecompress(
-              compressedBytecode, mRequest->mBytecodeOffset, bytecode)) {
+              compressedBytecode, mRequest->GetSRILength(), bytecode)) {
         return NS_ERROR_UNEXPECTED;
       }
     }
diff --git a/dom/script/ScriptLoader.cpp b/dom/script/ScriptLoader.cpp
index b851167e10cd..67b3651ad139 100644
--- a/dom/script/ScriptLoader.cpp
+++ b/dom/script/ScriptLoader.cpp
@@ -2685,10 +2685,12 @@ nsresult ScriptLoader::MaybePrepareForBytecodeEncodingAfterExecute(
   if (aRequest->IsMarkedForBytecodeEncoding()) {
     TRACE_FOR_TEST(aRequest->GetScriptLoadContext()->GetScriptElement(),
                    "scriptloader_encode");
+    // Check that the TranscodeBuffer which is going to receive the encoded
+    // bytecode only contains the SRI, and nothing more.
+    //
     // NOTE: This assertion will fail once we start encoding more data after the
     //       first encode.
-    MOZ_ASSERT(aRequest->mBytecodeOffset ==
-               aRequest->SRIAndBytecode().length());
+    MOZ_ASSERT(aRequest->GetSRILength() == aRequest->SRIAndBytecode().length());
     RegisterForBytecodeEncoding(aRequest);
     MOZ_ASSERT(IsAlreadyHandledForBytecodeEncodingPreparation(aRequest));
 
@@ -2981,7 +2983,7 @@ void ScriptLoader::EncodeRequestBytecode(JSContext* aCx,
   Vector<uint8_t> compressedBytecode;
   // TODO probably need to move this to a helper thread
   if (!ScriptBytecodeCompress(aRequest->SRIAndBytecode(),
-                              aRequest->mBytecodeOffset, compressedBytecode)) {
+                              aRequest->GetSRILength(), compressedBytecode)) {
     return;
   }
 
@@ -3342,10 +3344,13 @@ nsresult ScriptLoader::OnStreamComplete(
       JS::TranscodeBuffer& bytecode = aRequest->SRIAndBytecode();
       MOZ_ASSERT_IF(NS_SUCCEEDED(rv), bytecode.length() == sriLength);
 
-      aRequest->mBytecodeOffset = JS::AlignTranscodingBytecodeOffset(sriLength);
-      if (aRequest->mBytecodeOffset != sriLength) {
-        // We need extra padding after SRI hash.
-        if (!bytecode.resize(aRequest->mBytecodeOffset)) {
+      // TODO: (Bug 1800896) This code should be moved into SaveSRIHash, and the
+      // SRI out-param can be removed.
+      aRequest->SetSRILength(sriLength);
+      if (aRequest->GetSRILength() != sriLength) {
+        // The bytecode is aligned in the bytecode buffer, and space might be
+        // reserved for padding after the SRI hash.
+        if (!bytecode.resize(aRequest->GetSRILength())) {
           return NS_ERROR_OUT_OF_MEMORY;
         }
       }
diff --git a/js/loader/ScriptLoadRequest.h b/js/loader/ScriptLoadRequest.h
index d6edf5b0bd21..230c8ba5c010 100644
--- a/js/loader/ScriptLoadRequest.h
+++ b/js/loader/ScriptLoadRequest.h
@@ -259,6 +259,15 @@ class ScriptLoadRequest
                               bytecode.length() - offset);
   }
 
+  size_t GetSRILength() const {
+    MOZ_ASSERT(IsBytecode() || IsSource());
+    return mBytecodeOffset;
+  }
+  void SetSRILength(size_t sriLength) {
+    MOZ_ASSERT(IsBytecode() || IsSource());
+    mBytecodeOffset = JS::AlignTranscodingBytecodeOffset(sriLength);
+  }
+
   mozilla::CORSMode CORSMode() const { return mFetchOptions->mCORSMode; }
 
   void DropBytecodeCacheReferences();