intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 114 insertions, 0 deletions

diff --git a/library/cpp/yt/string/format.h b/library/cpp/yt/string/format.h
new file mode 100644
index 0000000000..9708fe5906
--- /dev/null
+++ b/library/cpp/yt/string/format.h
@@ -0,0 +1,114 @@
+#pragma once
+
+#include "string_builder.h"
+
+namespace NYT {
+
+////////////////////////////////////////////////////////////////////////////////
+
+/*
+ *  Format: a type-safe and fast formatting utility.
+ *
+ *  Basically works as a type-safe analogue of |sprintf| and is expected to
+ *  be backwards-compatible with the latter.
+ *
+ *  Like Go's |Sprintf|, supports the ultimate format specifier |v|
+ *  causing arguments to be emitted in default format.
+ *  This is the default and preferred way of formatting things,
+ *  which should be used in newer code.
+ *
+ *  |Format| may currently invoke |sprintf| internally for emitting numeric and some other
+ *  types. You can always write your own optimized implementation, if you wish :)
+ *
+ *  In additional to the usual |sprintf|, supports a number of non-standard flags:
+ *
+ *  |q|   Causes the argument to be surrounded with single quotes (|'|).
+ *        Applies to all types.
+ *
+ *  |Q|   Causes the argument to be surrounded with double quotes (|"|).
+ *        Applies to all types.
+ *
+ *  |l|   The argument is emitted in "lowercase" style.
+ *        Only applies to enums and bools.
+ *
+ *  The following argument types are supported:
+ *
+ *  Strings (including |const char*|, |TStringBuf|, and |TString|) and chars:
+ *  Emitted as is. Fast.
+ *
+ *  Numerics and pointers:
+ *  Emitted using |sprintf|. Maybe not that fast.
+ *
+ *  |bool|:
+ *  Emitted either as |True| and |False| or |true| and |false| (if lowercase mode is ON).
+ *
+ *  Enums:
+ *  Emitted in either camel (|SomeName|) or in lowercase-with-underscores style
+ *  (|some_name|, if lowercase mode is ON).
+ *
+ *  Nullables:
+ *  |std::nullopt| is emitted as |<null>|.
+ *
+ *  All others:
+ *  Emitted as strings by calling |ToString|.
+ *
+ */
+
+template <size_t Length, class... TArgs>
+void Format(TStringBuilderBase* builder, const char (&format)[Length], TArgs&&... args);
+template <class... TArgs>
+void Format(TStringBuilderBase* builder, TStringBuf format, TArgs&&... args);
+
+template <size_t Length, class... TArgs>
+TString Format(const char (&format)[Length], TArgs&&... args);
+template <class... TArgs>
+TString Format(TStringBuf format, TArgs&&... args);
+
+////////////////////////////////////////////////////////////////////////////////
+
+template <class TRange, class TFormatter>
+struct TFormattableView
+{
+    using TBegin = std::decay_t<decltype(std::declval<const TRange>().begin())>;
+    using TEnd = std::decay_t<decltype(std::declval<const TRange>().end())>;
+
+    TBegin RangeBegin;
+    TEnd RangeEnd;
+    TFormatter Formatter;
+    size_t Limit = std::numeric_limits<size_t>::max();
+
+    TBegin begin() const;
+    TEnd end() const;
+};
+
+//! Annotates a given #range with #formatter to be applied to each item.
+template <class TRange, class TFormatter>
+TFormattableView<TRange, TFormatter> MakeFormattableView(
+    const TRange& range,
+    TFormatter&& formatter);
+
+template <class TRange, class TFormatter>
+TFormattableView<TRange, TFormatter> MakeShrunkFormattableView(
+    const TRange& range,
+    TFormatter&& formatter,
+    size_t limit);
+
+////////////////////////////////////////////////////////////////////////////////
+
+template <class TFormatter>
+struct TFormatterWrapper
+{
+    TFormatter Formatter;
+};
+
+template <class TFormatter>
+TFormatterWrapper<TFormatter> MakeFormatterWrapper(
+    TFormatter&& formatter);
+
+////////////////////////////////////////////////////////////////////////////////
+
+} // namespace NYT
+
+#define FORMAT_INL_H_
+#include "format-inl.h"
+#undef FORMAT_INL_H_