ICU-22954 U_ICU_NAMESPACE_OR_INTERNAL, header-only localpointer

header-only parts of char16ptr.h

icu4c/source/common/unicode/char16ptr.h

@@ -9,10 +9,13 @@
 
 #include "unicode/utypes.h"
 
-#if U_SHOW_CPLUSPLUS_API
+#if U_SHOW_CPLUSPLUS_API || U_SHOW_CPLUSPLUS_HEADER_API
 
 #include <cstddef>
 #include <string_view>
+#include <type_traits>
+
+#endif
 
 /**
  * \file
@@ -21,8 +24,6 @@
  *        Also conversion functions from char16_t * to UChar * and OldUChar *.
  */
 
-U_NAMESPACE_BEGIN
-
 /**
  * \def U_ALIASING_BARRIER
  * Barrier for pointer anti-aliasing optimizations even across function boundaries.
@@ -36,6 +37,11 @@ U_NAMESPACE_BEGIN
 #   define U_ALIASING_BARRIER(ptr)
 #endif
 
+// ICU DLL-exported
+#if U_SHOW_CPLUSPLUS_API
+
+U_NAMESPACE_BEGIN
+
 /**
  * char16_t * wrapper with implicit conversion from distinct but bit-compatible pointer types.
  * @stable ICU 59
@@ -251,6 +257,34 @@ const char16_t *ConstChar16Ptr::get() const { return u_.cp; }
 #endif
 /// \endcond
 
+U_NAMESPACE_END
+
+#endif  // U_SHOW_CPLUSPLUS_API
+
+// Usable in header-only definitions
+#if U_SHOW_CPLUSPLUS_API || U_SHOW_CPLUSPLUS_HEADER_API
+
+namespace U_ICU_NAMESPACE_OR_INTERNAL {
+
+#ifndef U_FORCE_HIDE_INTERNAL_API
+/** @internal */
+template<typename T, typename = std::enable_if_t<std::is_same_v<T, UChar>>>
+inline const char16_t *uprv_char16PtrFromUChar(const T *p) {
+    if constexpr (std::is_same_v<UChar, char16_t>) {
+        return p;
+    } else {
+#if U_SHOW_CPLUSPLUS_API
+        return ConstChar16Ptr(p).get();
+#else
+#ifdef U_ALIASING_BARRIER
+        U_ALIASING_BARRIER(p);
+#endif
+        return reinterpret_cast<const char16_t *>(p);
+#endif
+    }
+}
+#endif
+
 /**
  * Converts from const char16_t * to const UChar *.
  * Includes an aliasing barrier if available.
@@ -307,6 +341,15 @@ inline OldUChar *toOldUCharPtr(char16_t *p) {
     return reinterpret_cast<OldUChar *>(p);
 }
 
+}  // U_ICU_NAMESPACE_OR_INTERNAL
+
+#endif  // U_SHOW_CPLUSPLUS_API || U_SHOW_CPLUSPLUS_HEADER_API
+
+// ICU DLL-exported
+#if U_SHOW_CPLUSPLUS_API
+
+U_NAMESPACE_BEGIN
+
 #ifndef U_FORCE_HIDE_INTERNAL_API
 /**
  * Is T convertible to a std::u16string_view or some other 16-bit string view?
@@ -379,6 +422,6 @@ inline std::u16string_view toU16StringViewNullable(const T& text) {
 
 U_NAMESPACE_END
 
-#endif /* U_SHOW_CPLUSPLUS_API */
+#endif  // U_SHOW_CPLUSPLUS_API
 
 #endif  // __CHAR16PTR_H__

icu4c/source/common/unicode/localpointer.h

@@ -21,7 +21,7 @@
 
 /**
  * \file
- * \brief C++ API: "Smart pointers" for use with and in ICU4C C++ code.
+ * \brief C++ header-only API: "Smart pointers" for use with and in ICU4C C++ code.
  *
  * These classes are inspired by
  * - std::auto_ptr
@@ -40,11 +40,11 @@
 
 #include "unicode/utypes.h"
 
-#if U_SHOW_CPLUSPLUS_API
+#if U_SHOW_CPLUSPLUS_API || U_SHOW_CPLUSPLUS_HEADER_API
 
 #include <memory>
 
-U_NAMESPACE_BEGIN
+namespace U_ICU_NAMESPACE_OR_INTERNAL {
 
 /**
  * "Smart pointer" base class; do not use directly: use LocalPointer etc.
@@ -603,7 +603,7 @@ public:
 }  // namespace internal
 #endif
 
-U_NAMESPACE_END
+}  // U_ICU_NAMESPACE_OR_INTERNAL
 
-#endif  /* U_SHOW_CPLUSPLUS_API */
+#endif  // U_SHOW_CPLUSPLUS_API || U_SHOW_CPLUSPLUS_HEADER_API
 #endif  /* __LOCALPOINTER_H__ */

icu4c/source/common/unicode/normlzr.h

@@ -801,8 +801,8 @@ Normalizer::compare(const UnicodeString &s1, const UnicodeString &s2,
                     uint32_t options,
                     UErrorCode &errorCode) {
   // all argument checking is done in unorm_compare
-  return unorm_compare(toUCharPtr(s1.getBuffer()), s1.length(),
-                       toUCharPtr(s2.getBuffer()), s2.length(),
+  return unorm_compare(U_ICU_NAMESPACE_OR_INTERNAL::toUCharPtr(s1.getBuffer()), s1.length(),
+                       U_ICU_NAMESPACE_OR_INTERNAL::toUCharPtr(s2.getBuffer()), s2.length(),
                        options,
                        &errorCode);
 }

icu4c/source/common/unicode/unistr.h

@@ -4676,7 +4676,7 @@ UnicodeString::startsWith(const UnicodeString& srcText,
 inline UBool
 UnicodeString::startsWith(ConstChar16Ptr srcChars, int32_t srcLength) const {
   if(srcLength < 0) {
-    srcLength = u_strlen(toUCharPtr(srcChars));
+    srcLength = u_strlen(U_ICU_NAMESPACE_OR_INTERNAL::toUCharPtr(srcChars));
   }
   return doEqualsSubstring(0, srcLength, srcChars, 0, srcLength);
 }
@@ -4684,7 +4684,7 @@ UnicodeString::startsWith(ConstChar16Ptr srcChars, int32_t srcLength) const {
 inline UBool
 UnicodeString::startsWith(const char16_t *srcChars, int32_t srcStart, int32_t srcLength) const {
   if(srcLength < 0) {
-    srcLength = u_strlen(toUCharPtr(srcChars));
+    srcLength = u_strlen(U_ICU_NAMESPACE_OR_INTERNAL::toUCharPtr(srcChars));
   }
   return doEqualsSubstring(0, srcLength, srcChars, srcStart, srcLength);
 }
@@ -4707,7 +4707,7 @@ inline UBool
 UnicodeString::endsWith(ConstChar16Ptr srcChars,
             int32_t srcLength) const {
   if(srcLength < 0) {
-    srcLength = u_strlen(toUCharPtr(srcChars));
+    srcLength = u_strlen(U_ICU_NAMESPACE_OR_INTERNAL::toUCharPtr(srcChars));
   }
   return doEqualsSubstring(length() - srcLength, srcLength, srcChars, 0, srcLength);
 }
@@ -4717,7 +4717,7 @@ UnicodeString::endsWith(const char16_t *srcChars,
             int32_t srcStart,
             int32_t srcLength) const {
   if(srcLength < 0) {
-    srcLength = u_strlen(toUCharPtr(srcChars + srcStart));
+    srcLength = u_strlen(U_ICU_NAMESPACE_OR_INTERNAL::toUCharPtr(srcChars + srcStart));
   }
   return doEqualsSubstring(length() - srcLength, srcLength,
                    srcChars, srcStart, srcLength);

icu4c/source/common/unicode/uset.h

@@ -32,13 +32,13 @@
 #include "unicode/utypes.h"
 #include "unicode/uchar.h"
 
-#if U_SHOW_CPLUSPLUS_API
+#if U_SHOW_CPLUSPLUS_API || U_SHOW_CPLUSPLUS_HEADER_API
 #include <string>
 #include <string_view>
 #include "unicode/char16ptr.h"
 #include "unicode/localpointer.h"
 #include "unicode/utf16.h"
-#endif   // U_SHOW_CPLUSPLUS_API
+#endif
 
 #ifndef USET_DEFINED
 
@@ -346,9 +346,9 @@ uset_openPatternOptions(const UChar* pattern, int32_t patternLength,
 U_CAPI void U_EXPORT2
 uset_close(USet* set);
 
-#if U_SHOW_CPLUSPLUS_API
+#if U_SHOW_CPLUSPLUS_API || U_SHOW_CPLUSPLUS_HEADER_API
 
-U_NAMESPACE_BEGIN
+namespace U_ICU_NAMESPACE_OR_INTERNAL {
 
 /**
  * \class LocalUSetPointer
@@ -361,7 +361,7 @@ U_NAMESPACE_BEGIN
  */
 U_DEFINE_LOCAL_OPEN_POINTER(LocalUSetPointer, USet, uset_close);
 
-U_NAMESPACE_END
+}  // U_ICU_NAMESPACE_OR_INTERNAL
 
 #endif
 
@@ -1658,7 +1658,7 @@ public:
             int32_t length;
             const UChar *uchars = uset_getString(uset, index, &length);
             // assert uchars != nullptr;
-            return {ConstChar16Ptr(uchars), static_cast<uint32_t>(length)};
+            return {uprv_char16PtrFromUChar(uchars), static_cast<size_t>(length)};
         }
         return {};
     }
@@ -1772,7 +1772,7 @@ public:
             int32_t length;
             const UChar *uchars = uset_getString(uset, index - rangeCount, &length);
             // assert uchars != nullptr;
-            return {ConstChar16Ptr(uchars), static_cast<uint32_t>(length)};
+            return {uprv_char16PtrFromUChar(uchars), static_cast<size_t>(length)};
         } else {
             return {};
         }

icu4c/source/common/unicode/uversion.h

@@ -125,7 +125,7 @@ typedef uint8_t UVersionInfo[U_MAX_VERSION_LENGTH];
         U_NAMESPACE_USE
 #   endif
 
-#ifndef U_HIDE_DRAFT_API
+#ifndef U_FORCE_HIDE_DRAFT_API
 /**
  * \def U_HEADER_NESTED_NAMESPACE
  * Nested namespace used inside U_ICU_NAMESPACE for header-only APIs.
@@ -150,22 +150,37 @@ typedef uint8_t UVersionInfo[U_MAX_VERSION_LENGTH];
  * @draft ICU 76
  */
 
+/**
+ * \def U_ICU_NAMESPACE_OR_INTERNAL
+ * Namespace used for header-only APIs that used to be regular C++ APIs.
+ * Different when used inside ICU to prevent public use of internal instantiations.
+ * Similar to U_HEADER_ONLY_NAMESPACE, but the public definition is the same as U_ICU_NAMESPACE.
+ * "U_ICU_NAMESPACE" or "U_ICU_NAMESPACE::internal".
+ *
+ * @draft ICU 77
+ */
+
 // The first test is the same as for defining U_EXPORT for Windows.
 #if defined(_MSC_VER) || (UPRV_HAS_DECLSPEC_ATTRIBUTE(__dllexport__) && \
                           UPRV_HAS_DECLSPEC_ATTRIBUTE(__dllimport__))
 #   define U_HEADER_NESTED_NAMESPACE header
+#   define U_ICU_NAMESPACE_OR_INTERNAL U_ICU_NAMESPACE
 #elif defined(U_COMBINED_IMPLEMENTATION) || defined(U_COMMON_IMPLEMENTATION) || \
         defined(U_I18N_IMPLEMENTATION) || defined(U_IO_IMPLEMENTATION) || \
         defined(U_LAYOUTEX_IMPLEMENTATION) || defined(U_TOOLUTIL_IMPLEMENTATION)
 #   define U_HEADER_NESTED_NAMESPACE internal
+#   define U_ICU_NAMESPACE_OR_INTERNAL U_ICU_NAMESPACE::internal
+    namespace U_ICU_NAMESPACE_OR_INTERNAL {}
+    using namespace U_ICU_NAMESPACE_OR_INTERNAL;
 #else
 #   define U_HEADER_NESTED_NAMESPACE header
+#   define U_ICU_NAMESPACE_OR_INTERNAL U_ICU_NAMESPACE
 #endif
 
 #define U_HEADER_ONLY_NAMESPACE U_ICU_NAMESPACE::U_HEADER_NESTED_NAMESPACE
 
 namespace U_HEADER_ONLY_NAMESPACE {}
-#endif  // U_HIDE_DRAFT_API
+#endif  // U_FORCE_HIDE_DRAFT_API
 
 #endif /* __cplusplus */
 

icu4c/source/i18n/unicode/ucol.h

@@ -1572,8 +1572,8 @@ class Predicate {
         return compare(
             ucol_strcoll(
                 collator,
-                toUCharPtr(lhs.getBuffer()), lhs.length(),
-                toUCharPtr(rhs.getBuffer()), rhs.length()),
+                U_ICU_NAMESPACE_OR_INTERNAL::toUCharPtr(lhs.getBuffer()), lhs.length(),
+                U_ICU_NAMESPACE_OR_INTERNAL::toUCharPtr(rhs.getBuffer()), rhs.length()),
             result);
     }