YT-27951: Add special formatter for truncated string

commit_hash:88bc9543595f9b630942d63aa1c3aee154056e92

1 files changed, 25 insertions, 0 deletions

diff --git a/library/cpp/yt/string/string.cpp b/library/cpp/yt/string/string.cpp
index d155da578e4..de9f41a5084 100644
--- a/library/cpp/yt/string/string.cpp
+++ b/library/cpp/yt/string/string.cpp
@@ -362,6 +362,31 @@ std::string TruncateString(std::string string, int lengthLimit, TStringBuf trunc
     return string;
 }
 
+TTruncatedStringView::TTruncatedStringView(const std::string& value, int limit)
+    : Value_(value)
+    , Limit_(limit)
+{ }
+
+void TTruncatedStringView::WriteToBuilder(TStringBuilderBase* builder, TStringBuf /* spec */) const
+{
+    int valueSize = std::ssize(Value_);
+    int maxSize = Limit_ + std::ssize(DefaultTruncatedMessage);
+    if (valueSize <= maxSize) {
+        builder->AppendString(Value_);
+        return;
+    }
+
+    char* begin = builder->Preallocate(maxSize);
+    memcpy(begin, Value_.data(), Limit_);
+    memcpy(begin + Limit_, DefaultTruncatedMessage.data(), DefaultTruncatedMessage.size());
+    builder->Advance(maxSize);
+}
+
+void FormatValue(TStringBuilderBase* builder, TTruncatedStringView value, TStringBuf spec)
+{
+    value.WriteToBuilder(builder, spec);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 
 } // namespace NYT