3 files changed, 49 insertions, 0 deletions
diff --git a/core/fxcrt/cfx_bytestring.cpp b/core/fxcrt/cfx_bytestring.cpp
index b83c59ffeb..967bcce0eb 100644
--- a/core/fxcrt/cfx_bytestring.cpp
+++ b/core/fxcrt/cfx_bytestring.cpp
@@ -867,8 +867,13 @@ FX_STRSIZE FX_ftoa(float d, char* buf) {
   }
   return buf_size;
 }
+
 CFX_ByteString CFX_ByteString::FormatFloat(float d, int precision) {
   char buf[32];
   FX_STRSIZE len = FX_ftoa(d, buf);
   return CFX_ByteString(buf, len);
 }
+
+std::ostream& operator<<(std::ostream& os, const CFX_ByteString& str) {
+  return os.write(str.c_str(), str.GetLength());
+}
diff --git a/core/fxcrt/cfx_bytestring.h b/core/fxcrt/cfx_bytestring.h
index 23e02491c5..7459f27745 100644
--- a/core/fxcrt/cfx_bytestring.h
+++ b/core/fxcrt/cfx_bytestring.h
@@ -233,6 +233,8 @@ inline CFX_ByteString operator+(const CFX_ByteStringC& str1,
 
 uint32_t FX_HashCode_GetA(const CFX_ByteStringC& str, bool bIgnoreCase);
 
+std::ostream& operator<<(std::ostream& os, const CFX_ByteString& str);
+
 namespace std {
 
 template <>
diff --git a/core/fxcrt/cfx_bytestring_unittest.cpp b/core/fxcrt/cfx_bytestring_unittest.cpp
index 609f89201b..86fa3830c2 100644
--- a/core/fxcrt/cfx_bytestring_unittest.cpp
+++ b/core/fxcrt/cfx_bytestring_unittest.cpp
@@ -1259,3 +1259,45 @@ TEST(fxcrt, EqualNoCase) {
   EXPECT_FALSE(str.EqualNoCase("a"));
   EXPECT_FALSE(str.EqualNoCase(""));
 }
+
+TEST(fxcrt, OStreamByteStringOverload) {
+  // Basic case
+  std::ostringstream stream;
+  CFX_ByteString str("def");
+  stream << "abc" << str << "ghi";
+  EXPECT_EQ("abcdefghi", stream.str());
+
+  // Changing the CFX_ByteString does not change the stream it was written to.
+  str = "123";
+  EXPECT_EQ("abcdefghi", stream.str());
+
+  // Writing it again to the stream will use the latest value.
+  stream.str("");
+  stream << "abc" << str << "ghi";
+  EXPECT_EQ("abc123ghi", stream.str());
+
+  char stringWithNulls[]{'x', 'y', '\0', 'z'};
+
+  // Writing a CFX_ByteString with nulls and no specified length treats it as
+  // a C-style null-terminated string.
+  str = CFX_ByteString(stringWithNulls);
+  EXPECT_EQ(2, str.GetLength());
+  stream.str("");
+  stream << str;
+  EXPECT_EQ(2u, stream.tellp());
+
+  // Writing a CFX_ByteString with nulls but specifying its length treats it as
+  // a C++-style string.
+  str = CFX_ByteString(stringWithNulls, 4);
+  EXPECT_EQ(4, str.GetLength());
+  stream.str("");
+  stream << str;
+  EXPECT_EQ(4u, stream.tellp());
+
+  // << operators can be chained.
+  CFX_ByteString str1("abc");
+  CFX_ByteString str2("def");
+  stream.str("");
+  stream << str1 << str2;
+  EXPECT_EQ("abcdef", stream.str());
+}