Commit a0841b59 authored by Brad King's avatar Brad King

String: Add support for a ""_s string literal syntax

Create a `static_string_view` type that binds only to the static storage
of string literals.  Teach `cm::String` to borrow from these implicitly.
parent 9d5fe8e9
......@@ -377,6 +377,7 @@ set(SRCS
cmake.h
cm_string_view.cxx
cm_string_view.hxx
cm_static_string_view.hxx
cmCommand.cxx
cmCommand.h
......
......@@ -5,6 +5,7 @@
#include "cmConfigure.h" // IWYU pragma: keep
#include "cm_static_string_view.hxx"
#include "cm_string_view.hxx"
#include <algorithm>
......@@ -89,6 +90,12 @@ struct IntoString<string_view> : std::true_type
static std::string into_string(string_view s) { return std::string(s); }
};
template <>
struct IntoString<static_string_view> : std::true_type
{
static string_view into_string(static_string_view s) { return s; }
};
template <>
struct IntoString<char> : std::true_type
{
......@@ -156,6 +163,12 @@ struct AsStringView<string_view> : std::true_type
static string_view view(string_view const& s) { return s; }
};
template <>
struct AsStringView<static_string_view> : std::true_type
{
static string_view view(static_string_view const& s) { return s; }
};
template <>
struct AsStringView<String> : std::true_type
{
......@@ -370,7 +383,7 @@ public:
}
/** Assign to an empty string. */
void clear() { *this = String(string_view("", 0), Private()); }
void clear() { *this = ""_s; }
/** Insert 'count' copies of 'ch' at position 'index'. */
String& insert(size_type index, size_type count, char ch);
......
/* Distributed under the OSI-approved BSD 3-Clause License. See accompanying
file Copyright.txt or https://cmake.org/licensing for details. */
#ifndef cm_static_string_view_hxx
#define cm_static_string_view_hxx
#include "cmConfigure.h" // IWYU pragma: keep
#include "cm_string_view.hxx"
#include <cstddef>
namespace cm {
/** A string_view that only binds to static storage.
*
* This is used together with the `""_s` user-defined literal operator
* to construct a type-safe abstraction of a string_view that only views
* statically allocated strings. These strings are const and available
* for the entire lifetime of the program.
*/
class static_string_view : public string_view
{
static_string_view(string_view v)
: string_view(v)
{
}
friend static_string_view operator"" _s(const char* data, size_t size);
};
/** Create a static_string_view using `""_s` literal syntax. */
inline static_string_view operator"" _s(const char* data, size_t size)
{
return string_view(data, size);
}
} // namespace cm
using cm::operator"" _s;
#endif
......@@ -3,6 +3,7 @@
#include "cmString.hxx"
#include "cm_static_string_view.hxx"
#include "cm_string_view.hxx"
#include <cstring>
......@@ -254,6 +255,36 @@ static bool testConstructFromN()
return true;
}
static const auto staticStringView = "abc"_s;
static bool testFromStaticStringView(cm::String str)
{
cm::String const& str_const = str;
ASSERT_TRUE(str_const.data() == staticStringView.data());
ASSERT_TRUE(str_const.size() == staticStringView.size());
ASSERT_TRUE(str.c_str() == staticStringView);
cm::String substr = str.substr(1);
cm::String const& substr_const = substr;
ASSERT_TRUE(substr_const.data() == &staticStringView[1]);
ASSERT_TRUE(substr_const.size() == 2);
ASSERT_TRUE(substr.c_str() == &staticStringView[1]);
return true;
}
static bool testConstructFromStaticStringView()
{
std::cout << "testConstructFromStaticStringView()\n";
return testFromStaticStringView(staticStringView);
}
static bool testAssignFromStaticStringView()
{
std::cout << "testAssignFromStaticStringView()\n";
cm::String str;
str = staticStringView;
return testFromStaticStringView(str);
}
static bool testConstructCopy()
{
std::cout << "testConstructCopy()\n";
......@@ -730,7 +761,7 @@ static bool testMethod_substr_AtEnd(cm::String str)
static bool testMethod_substr_AtEndBorrowed()
{
std::cout << "testMethod_substr_AtEndBorrowed()\n";
return testMethod_substr_AtEnd(cm::String::borrow("abc"));
return testMethod_substr_AtEnd("abc"_s);
}
static bool testMethod_substr_AtEndOwned()
......@@ -784,7 +815,7 @@ static bool testMethod_substr_AtStart(cm::String str)
static bool testMethod_substr_AtStartBorrowed()
{
std::cout << "testMethod_substr_AtStartBorrowed()\n";
return testMethod_substr_AtStart(cm::String::borrow("abc"));
return testMethod_substr_AtStart("abc"_s);
}
static bool testMethod_substr_AtStartOwned()
......@@ -977,6 +1008,14 @@ static bool testAddition()
ASSERT_TRUE("a" + (cm::String("b") + "c") + "d" == "abcd");
ASSERT_TRUE("abcd" == "a" + (cm::String("b") + "c") + "d");
}
{
ASSERT_TRUE(cm::String("a"_s) + "b"_s == "ab"_s);
ASSERT_TRUE("ab"_s == "a"_s + cm::String("b"_s));
ASSERT_TRUE("a"_s + cm::String("b"_s) + "c"_s == "abc"_s);
ASSERT_TRUE("abc"_s == "a"_s + cm::String("b"_s) + "c"_s);
ASSERT_TRUE("a"_s + (cm::String("b"_s) + "c"_s) + "d"_s == "abcd"_s);
ASSERT_TRUE("abcd"_s == "a"_s + (cm::String("b"_s) + "c"_s) + "d"_s);
}
{
const char* a = "a";
const char* b = "b";
......@@ -1101,6 +1140,9 @@ int testString(int /*unused*/, char* /*unused*/ [])
if (!testConstructFromN()) {
return 1;
}
if (!testConstructFromStaticStringView()) {
return 1;
}
if (!testConstructCopy()) {
return 1;
}
......@@ -1137,6 +1179,9 @@ int testString(int /*unused*/, char* /*unused*/ [])
if (!testAssignFromInitList()) {
return 1;
}
if (!testAssignFromStaticStringView()) {
return 1;
}
if (!testOperatorBool()) {
return 1;
}
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment