zlib: switch to lazy init for zlib streams

PR-URL: https://github.com/nodejs/node/pull/34048
Reviewed-By: Anna Henningsen <anna@addaleax.net>

1 files changed, 45 insertions, 14 deletions

diff --git a/src/node_zlib.cc b/src/node_zlib.cc
index 85e87327c07..efb11debf8f 100644
--- a/src/node_zlib.cc
+++ b/src/node_zlib.cc
@@ -139,8 +139,8 @@ class ZlibContext : public MemoryRetainer {
   CompressionError ResetStream();
 
   // Zlib-specific:
-  CompressionError Init(int level, int window_bits, int mem_level, int strategy,
-                        std::vector<unsigned char>&& dictionary);
+  void Init(int level, int window_bits, int mem_level, int strategy,
+            std::vector<unsigned char>&& dictionary);
   void SetAllocationFunctions(alloc_func alloc, free_func free, void* opaque);
   CompressionError SetParams(int level, int strategy);
 
@@ -157,7 +157,10 @@ class ZlibContext : public MemoryRetainer {
  private:
   CompressionError ErrorForMessage(const char* message) const;
   CompressionError SetDictionary();
+  bool InitZlib();
 
+  Mutex mutex_;  // Protects zlib_init_done_.
+  bool zlib_init_done_ = false;
   int err_ = 0;
   int flush_ = 0;
   int level_ = 0;
@@ -615,13 +618,8 @@ class ZlibStream : public CompressionStream<ZlibContext> {
     AllocScope alloc_scope(wrap);
     wrap->context()->SetAllocationFunctions(
         AllocForZlib, FreeForZlib, static_cast<CompressionStream*>(wrap));
-    const CompressionError err =
-        wrap->context()->Init(level, window_bits, mem_level, strategy,
-                              std::move(dictionary));
-    if (err.IsError())
-      wrap->EmitError(err);
-
-    return args.GetReturnValue().Set(!err.IsError());
+    wrap->context()->Init(level, window_bits, mem_level, strategy,
+                          std::move(dictionary));
   }
 
   static void Params(const FunctionCallbackInfo<Value>& args) {
@@ -724,6 +722,15 @@ using BrotliEncoderStream = BrotliCompressionStream<BrotliEncoderContext>;
 using BrotliDecoderStream = BrotliCompressionStream<BrotliDecoderContext>;
 
 void ZlibContext::Close() {
+  {
+    Mutex::ScopedLock lock(mutex_);
+    if (!zlib_init_done_) {
+      dictionary_.clear();
+      mode_ = NONE;
+      return;
+    }
+  }
+
   CHECK_LE(mode_, UNZIP);
 
   int status = Z_OK;
@@ -742,6 +749,11 @@ void ZlibContext::Close() {
 
 
 void ZlibContext::DoThreadPoolWork() {
+  bool first_init_call = InitZlib();
+  if (first_init_call && err_ != Z_OK) {
+    return;
+  }
+
   const Bytef* next_expected_header_byte = nullptr;
 
   // If the avail_out is left at 0, then it means that it ran out
@@ -897,6 +909,11 @@ CompressionError ZlibContext::GetErrorInfo() const {
 
 
 CompressionError ZlibContext::ResetStream() {
+  bool first_init_call = InitZlib();
+  if (first_init_call && err_ != Z_OK) {
+    return ErrorForMessage("Failed to init stream before reset");
+  }
+
   err_ = Z_OK;
 
   switch (mode_) {
@@ -930,7 +947,7 @@ void ZlibContext::SetAllocationFunctions(alloc_func alloc,
 }
 
 
-CompressionError ZlibContext::Init(
+void ZlibContext::Init(
     int level, int window_bits, int mem_level, int strategy,
     std::vector<unsigned char>&& dictionary) {
   if (!((window_bits == 0) &&
@@ -974,6 +991,15 @@ CompressionError ZlibContext::Init(
     window_bits_ *= -1;
   }
 
+  dictionary_ = std::move(dictionary);
+}
+
+bool ZlibContext::InitZlib() {
+  Mutex::ScopedLock lock(mutex_);
+  if (zlib_init_done_) {
+    return false;
+  }
+
   switch (mode_) {
     case DEFLATE:
     case GZIP:
@@ -995,15 +1021,15 @@ CompressionError ZlibContext::Init(
       UNREACHABLE();
   }
 
-  dictionary_ = std::move(dictionary);
-
   if (err_ != Z_OK) {
     dictionary_.clear();
     mode_ = NONE;
-    return ErrorForMessage("zlib error");
+    return true;
   }
 
-  return SetDictionary();
+  SetDictionary();
+  zlib_init_done_ = true;
+  return true;
 }
 
 
@@ -1040,6 +1066,11 @@ CompressionError ZlibContext::SetDictionary() {
 
 
 CompressionError ZlibContext::SetParams(int level, int strategy) {
+  bool first_init_call = InitZlib();
+  if (first_init_call && err_ != Z_OK) {
+    return ErrorForMessage("Failed to init stream before set parameters");
+  }
+
   err_ = Z_OK;
 
   switch (mode_) {