src: stop using v8::BackingStore::Reallocate

It's being deprecated by V8.
Explicitly allocate a new ArrayBuffer and copy the data when needed
instead.

Fixes: #52234
Co-authored-by: Joyee Cheung <joyeec9h3@gmail.com>
PR-URL: #52292
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

src/crypto/crypto_cipher.cc

@@ -830,10 +830,15 @@ CipherBase::UpdateResult CipherBase::Update(
                            len);
 
   CHECK_LE(static_cast<size_t>(buf_len), (*out)->ByteLength());
-  if (buf_len == 0)
+  if (buf_len == 0) {
     *out = ArrayBuffer::NewBackingStore(env()->isolate(), 0);
-  else
-    *out = BackingStore::Reallocate(env()->isolate(), std::move(*out), buf_len);
+  } else if (static_cast<size_t>(buf_len) != (*out)->ByteLength()) {
+    std::unique_ptr<BackingStore> old_out = std::move(*out);
+    *out = ArrayBuffer::NewBackingStore(env()->isolate(), buf_len);
+    memcpy(static_cast<char*>((*out)->Data()),
+           static_cast<char*>(old_out->Data()),
+           buf_len);
+  }
 
   // When in CCM mode, EVP_CipherUpdate will fail if the authentication tag is
   // invalid. In that case, remember the error and throw in final().
@@ -921,11 +926,14 @@ bool CipherBase::Final(std::unique_ptr<BackingStore>* out) {
                             &out_len) == 1;
 
     CHECK_LE(static_cast<size_t>(out_len), (*out)->ByteLength());
-    if (out_len > 0) {
-      *out =
-        BackingStore::Reallocate(env()->isolate(), std::move(*out), out_len);
-    } else {
+    if (out_len == 0) {
       *out = ArrayBuffer::NewBackingStore(env()->isolate(), 0);
+    } else if (static_cast<size_t>(out_len) != (*out)->ByteLength()) {
+      std::unique_ptr<BackingStore> old_out = std::move(*out);
+      *out = ArrayBuffer::NewBackingStore(env()->isolate(), out_len);
+      memcpy(static_cast<char*>((*out)->Data()),
+             static_cast<char*>(old_out->Data()),
+             out_len);
     }
 
     if (ok && kind_ == kCipher && IsAuthenticatedMode()) {
@@ -1025,10 +1033,15 @@ bool PublicKeyCipher::Cipher(
   }
 
   CHECK_LE(out_len, (*out)->ByteLength());
-  if (out_len > 0)
-    *out = BackingStore::Reallocate(env->isolate(), std::move(*out), out_len);
-  else
+  if (out_len == 0) {
     *out = ArrayBuffer::NewBackingStore(env->isolate(), 0);
+  } else if (out_len != (*out)->ByteLength()) {
+    std::unique_ptr<BackingStore> old_out = std::move(*out);
+    *out = ArrayBuffer::NewBackingStore(env->isolate(), out_len);
+    memcpy(static_cast<char*>((*out)->Data()),
+           static_cast<char*>(old_out->Data()),
+           out_len);
+  }
 
   return true;
 }

src/crypto/crypto_sig.cc

@@ -99,10 +99,15 @@ std::unique_ptr<BackingStore> Node_SignFinal(Environment* env,
       EVP_PKEY_sign(pkctx.get(), static_cast<unsigned char*>(sig->Data()),
                     &sig_len, m, m_len)) {
     CHECK_LE(sig_len, sig->ByteLength());
-    if (sig_len == 0)
+    if (sig_len == 0) {
       sig = ArrayBuffer::NewBackingStore(env->isolate(), 0);
-    else
-      sig = BackingStore::Reallocate(env->isolate(), std::move(sig), sig_len);
+    } else if (sig_len != sig->ByteLength()) {
+      std::unique_ptr<BackingStore> old_sig = std::move(sig);
+      sig = ArrayBuffer::NewBackingStore(env->isolate(), sig_len);
+      memcpy(static_cast<char*>(sig->Data()),
+             static_cast<char*>(old_sig->Data()),
+             sig_len);
+    }
     return sig;
   }
 

src/node_buffer.cc

@@ -324,8 +324,13 @@ MaybeLocal<Object> New(Isolate* isolate,
     CHECK(actual <= length);
 
     if (LIKELY(actual > 0)) {
-      if (actual < length)
-        store = BackingStore::Reallocate(isolate, std::move(store), actual);
+      if (actual < length) {
+        std::unique_ptr<BackingStore> old_store = std::move(store);
+        store = ArrayBuffer::NewBackingStore(isolate, actual);
+        memcpy(static_cast<char*>(store->Data()),
+               static_cast<char*>(old_store->Data()),
+               actual);
+      }
       Local<ArrayBuffer> buf = ArrayBuffer::New(isolate, std::move(store));
       Local<Object> obj;
       if (UNLIKELY(!New(isolate, buf, 0, actual).ToLocal(&obj)))

src/node_http2.cc

@@ -2029,9 +2029,14 @@ void Http2Session::OnStreamRead(ssize_t nread, const uv_buf_t& buf_) {
 
   statistics_.data_received += nread;
 
-  if (LIKELY(stream_buf_offset_ == 0)) {
+  if (LIKELY(stream_buf_offset_ == 0 &&
+             static_cast<size_t>(nread) != bs->ByteLength())) {
     // Shrink to the actual amount of used data.
-    bs = BackingStore::Reallocate(env()->isolate(), std::move(bs), nread);
+    std::unique_ptr<BackingStore> old_bs = std::move(bs);
+    bs = ArrayBuffer::NewBackingStore(env()->isolate(), nread);
+    memcpy(static_cast<char*>(bs->Data()),
+           static_cast<char*>(old_bs->Data()),
+           nread);
   } else {
     // This is a very unlikely case, and should only happen if the ReadStart()
     // call in OnStreamAfterWrite() immediately provides data. If that does

src/stream_base.cc

@@ -679,7 +679,13 @@ void EmitToJSStreamListener::OnStreamRead(ssize_t nread, const uv_buf_t& buf_) {
   }
 
   CHECK_LE(static_cast<size_t>(nread), bs->ByteLength());
-  bs = BackingStore::Reallocate(isolate, std::move(bs), nread);
+  if (static_cast<size_t>(nread) != bs->ByteLength()) {
+    std::unique_ptr<BackingStore> old_bs = std::move(bs);
+    bs = ArrayBuffer::NewBackingStore(isolate, nread);
+    memcpy(static_cast<char*>(bs->Data()),
+           static_cast<char*>(old_bs->Data()),
+           nread);
+  }
 
   stream->CallJSOnreadMethod(nread, ArrayBuffer::New(isolate, std::move(bs)));
 }

src/udp_wrap.cc

@@ -764,9 +764,13 @@ void UDPWrap::OnRecv(ssize_t nread,
     return;
   } else if (nread == 0) {
     bs = ArrayBuffer::NewBackingStore(isolate, 0);
-  } else {
+  } else if (static_cast<size_t>(nread) != bs->ByteLength()) {
     CHECK_LE(static_cast<size_t>(nread), bs->ByteLength());
-    bs = BackingStore::Reallocate(isolate, std::move(bs), nread);
+    std::unique_ptr<BackingStore> old_bs = std::move(bs);
+    bs = ArrayBuffer::NewBackingStore(isolate, nread);
+    memcpy(static_cast<char*>(bs->Data()),
+           static_cast<char*>(old_bs->Data()),
+           nread);
   }
 
   Local<Object> address;