CMakePresets.json: Add ${sourceDirName} macro

Fixes: #21312

Help/manual/cmake-presets.7.rst

@@ -308,6 +308,11 @@ Format
 
     Path to the project source directory's parent directory.
 
+  ``${sourceDirName}``
+
+    The last filename component of ``${sourceDir}``. For example, if
+    ``${sourceDir}`` is ``/path/to/source``, this would be ``source``.
+
   ``${presetName}``
 
     Name specified in the preset's ``name`` field.

Source/cmCMakePresetsFile.cxx

@@ -638,6 +638,10 @@ ExpandMacroResult ExpandMacro(const cmCMakePresetsFile& file,
       out += cmSystemTools::GetParentDirectory(file.SourceDir);
       return ExpandMacroResult::Ok;
     }
+    if (macroName == "sourceDirName") {
+      out += cmSystemTools::GetFilenameName(file.SourceDir);
+      return ExpandMacroResult::Ok;
+    }
     if (macroName == "presetName") {
       out += preset.Name;
       return ExpandMacroResult::Ok;

Tests/RunCMake/CMakePresets/CMakePresets.json.in

@@ -72,6 +72,7 @@
         "TEST_DOLLAR": {
           "value": "${dollar}"
         },
+        "TEST_SOURCE_DIR_NAME": "${sourceDirName}",
         "TEST_ENV_REF": "$env{TEST_ENV_REF}",
         "TEST_ENV": "$env{TEST_ENV}",
         "TEST_D_ENV_REF": "$env{TEST_D_ENV_REF}",

Tests/RunCMake/CMakePresets/Good-stdout.txt

@@ -26,6 +26,7 @@ Preset CMake variables:
   TEST_PRESET_NAME:STRING="xGoodx"
   TEST_SOURCE_DIR:PATH="[^
 ]*/Tests/RunCMake/CMakePresets/Good"
+  TEST_SOURCE_DIR_NAME="Good"
   TEST_SOURCE_LIST:FILEPATH="[^
 ]*/Tests/RunCMake/CMakePresets/Good/CMakeLists\.txt"
   TEST_SOURCE_PARENT_DIR:PATH="[^

Tests/RunCMake/CMakePresets/Good.cmake

@@ -17,6 +17,7 @@ test_variable(TEST_UNTYPED_BOOL_FALSE "UNINITIALIZED" "FALSE")
 test_variable(TEST_PRESET_NAME "STRING" "xGoodx")
 test_variable(TEST_GENERATOR "UNINITIALIZED" "x${CMAKE_GENERATOR}x")
 test_variable(TEST_DOLLAR "UNINITIALIZED" "$")
+test_variable(TEST_SOURCE_DIR_NAME "UNINITIALIZED" "Good")
 test_variable(TEST_ENV_REF "UNINITIALIZED" "Environment variable")
 test_variable(TEST_ENV "UNINITIALIZED" "Environment variable")
 test_variable(TEST_D_ENV_REF "UNINITIALIZED" "xEnvironment variablex")