Rework StringRef interface and internals

Now it no longer tries to be this weird hybrid between an owning and non-owning reference, and is only ever non-owning. This is also reflected in its interface, for example `StringRef::isNullTerminated` is now public, and `StringRef::c_str()` has the precondition that it is true. Overview of the changes: * The `StringRef::m_data` member has been completely removed, as it had no more uses. * `StringRef::isSubstring()` has been made public and renamed to `StringRef::isNullTerminated()`, so that the name reflects what the method actually does. * `StringRef::currentData()` has been renamed to `StringRef::data()`, to be in line with common C++ containers and container-alikes. * `StringRef::c_str()` will no longer silently make copies. It instead has a precondition that `isNullTerminated()` is true. * If the user needs a null-terminated string, they should use the `std::string` conversion operator and call `c_str()` on the resulting `std::string`. * Some small optimizations in various places. * Basic functionality is now `constexpr`.
2025-09-17 18:35:40 +02:00 · 2019-10-21 17:44:11 +02:00
parent 87b745da66
commit 50cc14c94c
8 changed files with 317 additions and 417 deletions
--- a/projects/SelfTest/Baselines/xml.sw.approved.txt
+++ b/projects/SelfTest/Baselines/xml.sw.approved.txt
@@ -9846,6 +9846,14 @@ Message from section two
            0 == 0
          </Expanded>
        </Expression>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+          <Original>
+            empty.isNullTerminated()
+          </Original>
+          <Expanded>
+            true
+          </Expanded>
+        </Expression>
        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
          <Original>
            std::strcmp( empty.c_str(), "" ) == 0
@@ -9854,7 +9862,7 @@ Message from section two
            0 == 0
          </Expanded>
        </Expression>
-        <OverallResults successes="3" failures="0" expectedFailures="0"/>
+        <OverallResults successes="4" failures="0" expectedFailures="0"/>
      </Section>
      <Section name="From string literal" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
@@ -9875,10 +9883,10 @@ Message from section two
        </Expression>
        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
          <Original>
-            isSubstring( s ) == false
+            s.isNullTerminated()
          </Original>
          <Expanded>
-            false == false
+            true
          </Expanded>
        </Expression>
        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
@@ -9889,33 +9897,30 @@ Message from section two
            0 == 0
          </Expanded>
        </Expression>
-        <Section name="c_str() does not cause copy" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-            <Original>
-              isOwned( s ) == false
-            </Original>
-            <Expanded>
-              false == false
-            </Expanded>
-          </Expression>
-          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-            <Original>
-              s.c_str() == rawChars
-            </Original>
-            <Expanded>
-              "hello" == "hello"
-            </Expanded>
-          </Expression>
-          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-            <Original>
-              isOwned( s ) == false
-            </Original>
-            <Expanded>
-              false == false
-            </Expanded>
-          </Expression>
-          <OverallResults successes="3" failures="0" expectedFailures="0"/>
-        </Section>
+        <Expression success="true" type="REQUIRE_NOTHROW" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+          <Original>
+            s.c_str()
+          </Original>
+          <Expanded>
+            s.c_str()
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+          <Original>
+            s.c_str() == rawChars
+          </Original>
+          <Expanded>
+            "hello" == "hello"
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+          <Original>
+            s.data() == rawChars
+          </Original>
+          <Expanded>
+            "hello" == "hello"
+          </Expanded>
+        </Expression>
        <OverallResults successes="7" failures="0" expectedFailures="0"/>
      </Section>
      <Section name="From sub-string" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
@@ -9927,28 +9932,28 @@ Message from section two
            original == "original"
          </Expanded>
        </Expression>
-        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+        <Expression success="true" type="REQUIRE_FALSE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
          <Original>
-            isSubstring( original )
+            !(original.isNullTerminated())
          </Original>
          <Expanded>
-            true
+            !false
          </Expanded>
        </Expression>
-        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+        <Expression success="true" type="REQUIRE_THROWS" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
          <Original>
-            isOwned( original ) == false
+            original.c_str()
          </Original>
          <Expanded>
-            false == false
+            original.c_str()
          </Expanded>
        </Expression>
-        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+        <Expression success="true" type="REQUIRE_NOTHROW" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
          <Original>
-            isOwned( original )
+            original.data()
          </Original>
          <Expanded>
-            true
+            original.data()
          </Expanded>
        </Expression>
        <OverallResults successes="4" failures="0" expectedFailures="0"/>
@@ -9973,7 +9978,7 @@ Message from section two
          </Expression>
          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
            <Original>
-              std::strcmp( ss.c_str(), "hello" ) == 0
+              std::strncmp( ss.data(), "hello", 5 ) == 0
            </Original>
            <Expanded>
              0 == 0
@@ -9991,79 +9996,6 @@ Message from section two
        </Section>
        <OverallResults successes="4" failures="0" expectedFailures="0"/>
      </Section>
-      <Section name="Substrings" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-        <Section name="c_str() causes copy" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-            <Original>
-              isSubstring( ss )
-            </Original>
-            <Expanded>
-              true
-            </Expanded>
-          </Expression>
-          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-            <Original>
-              isOwned( ss ) == false
-            </Original>
-            <Expanded>
-              false == false
-            </Expanded>
-          </Expression>
-          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-            <Original>
-              rawChars == s.currentData()
-            </Original>
-            <Expanded>
-              "hello world!" == "hello world!"
-            </Expanded>
-          </Expression>
-          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-            <Original>
-              ss.c_str() != rawChars
-            </Original>
-            <Expanded>
-              "hello" != "hello world!"
-            </Expanded>
-          </Expression>
-          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-            <Original>
-              isOwned( ss )
-            </Original>
-            <Expanded>
-              true
-            </Expanded>
-          </Expression>
-          <Section name="Self-assignment after substring" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-            <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-              <Original>
-                isOwned(ss) == false
-              </Original>
-              <Expanded>
-                false == false
-              </Expanded>
-            </Expression>
-            <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-              <Original>
-                ss == "hello"
-              </Original>
-              <Expanded>
-                hello == "hello"
-              </Expanded>
-            </Expression>
-            <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-              <Original>
-                rawChars == ss.currentData()
-              </Original>
-              <Expanded>
-                "hello world!" == "hello world!"
-              </Expanded>
-            </Expression>
-            <OverallResults successes="3" failures="0" expectedFailures="0"/>
-          </Section>
-          <OverallResults successes="8" failures="0" expectedFailures="0"/>
-        </Section>
-        <OverallResults successes="8" failures="0" expectedFailures="0"/>
-      </Section>
      <Section name="Substrings" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
        <Section name="non-zero-based substring" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
@@ -10090,7 +10022,7 @@ Message from section two
        <Section name="Pointer values of full refs should match" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
            <Original>
-              s.c_str() == s2.c_str()
+              s.data() == s2.data()
            </Original>
            <Expanded>
              "hello world!" == "hello world!"
@@ -10101,13 +10033,13 @@ Message from section two
        <OverallResults successes="1" failures="0" expectedFailures="0"/>
      </Section>
      <Section name="Substrings" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-        <Section name="Pointer values of substring refs should not match" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+        <Section name="Pointer values of substring refs should also match" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
            <Original>
-              s.c_str() != ss.c_str()
+              s.data() == ss.data()
            </Original>
            <Expanded>
-              "hello world!" != "hello"
+              "hello world!" == "hello world!"
            </Expanded>
          </Expression>
          <OverallResults successes="1" failures="0" expectedFailures="0"/>
@@ -10128,24 +10060,46 @@ Message from section two
        </Section>
        <OverallResults successes="1" failures="0" expectedFailures="0"/>
      </Section>
-      <Section name="Comparisons" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
-        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+      <Section name="Substrings" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+        <Section name="Substring off the end are trimmed" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+            <Original>
+              std::strcmp(ss.c_str(), "world!") == 0
+            </Original>
+            <Expanded>
+              0 == 0
+            </Expanded>
+          </Expression>
+          <OverallResults successes="1" failures="0" expectedFailures="0"/>
+        </Section>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Comparisons are deep" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
          <Original>
-            StringRef("hello") == StringRef("hello")
+            buffer1 != buffer2
          </Original>
          <Expanded>
-            hello == hello
+            "Hello" != "Hello"
          </Expanded>
        </Expression>
        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
          <Original>
-            StringRef("hello") != StringRef("cello")
+            left == right
          </Original>
          <Expanded>
-            hello != cello
+            Hello == Hello
          </Expanded>
        </Expression>
-        <OverallResults successes="2" failures="0" expectedFailures="0"/>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+          <Original>
+            left != left.substr(0, 3)
+          </Original>
+          <Expanded>
+            Hello != Hel
+          </Expanded>
+        </Expression>
+        <OverallResults successes="3" failures="0" expectedFailures="0"/>
      </Section>
      <Section name="from std::string" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
        <Section name="implicitly constructed" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
@@ -10259,6 +10213,15 @@ Message from section two
      </Section>
      <OverallResult success="true"/>
    </TestCase>
+    <TestCase name="StringRef at compilation time" tags="[StringRef][Strings][constexpr]" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+      <Section name="Simple constructors" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+        <OverallResults successes="5" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="UDL construction" filename="projects/<exe-name>/IntrospectiveTests/String.tests.cpp" >
+        <OverallResults successes="6" failures="0" expectedFailures="0"/>
+      </Section>
+      <OverallResult success="true"/>
+    </TestCase>
    <TestCase name="Stringifying std::chrono::duration helpers" tags="[chrono][toString]" filename="projects/<exe-name>/UsageTests/ToStringChrono.tests.cpp" >
      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/ToStringChrono.tests.cpp" >
        <Original>
@@ -15427,7 +15390,7 @@ loose text artifact
      </Section>
      <OverallResult success="true"/>
    </TestCase>
-    <OverallResults successes="1469" failures="149" expectedFailures="21"/>
+    <OverallResults successes="1475" failures="149" expectedFailures="21"/>
  </Group>
-  <OverallResults successes="1469" failures="148" expectedFailures="21"/>
+  <OverallResults successes="1475" failures="148" expectedFailures="21"/>
 </Catch>