cmLocalGenerator: Clarify GetIncludeFlags signature

Make the `config` argument non-optional so all callers must be explicit.
Convert the path style argument to an enumeration to make its role clear
at call sites.

The path style argument is implemented by `ConvertToIncludeReference`,
which was introduced with the Ninja generator by commit 5b114c9bee
(Introduce a cmLocalGenerator::ConvertToIncludeReference function,
2011-09-07, v2.8.7~187^2~4).  Its only purpose is to allow the Ninja
generator to use relative paths in `-I` flags.  Add a comment explaining
this role.

1 files changed, 19 insertions, 11 deletions

diff --git a/Source/cmLocalGenerator.h b/Source/cmLocalGenerator.h
index e48849a..f597120 100644
--- a/Source/cmLocalGenerator.h
+++ b/Source/cmLocalGenerator.h
@@ -171,13 +171,19 @@ public:
                                             cmGeneratorTarget* target,
                                             const std::string& config,
                                             const std::string& lang);
+
+  enum class IncludePathStyle
+  {
+    Default,
+    Absolute,
+  };
+
   //! Get the include flags for the current makefile and language
-  std::string GetIncludeFlags(const std::vector<std::string>& includes,
-                              cmGeneratorTarget* target,
-                              const std::string& lang,
-                              bool forceFullPaths = false,
-                              bool forResponseFile = false,
-                              const std::string& config = "");
+  std::string GetIncludeFlags(
+    std::vector<std::string> const& includes, cmGeneratorTarget* target,
+    std::string const& lang, std::string const& config,
+    bool forResponseFile = false,
+    IncludePathStyle pathStyle = IncludePathStyle::Default);
 
   using GeneratorTargetVector =
     std::vector<std::unique_ptr<cmGeneratorTarget>>;
@@ -256,11 +262,6 @@ public:
   bool GetRealDependency(const std::string& name, const std::string& config,
                          std::string& dep);
 
-  virtual std::string ConvertToIncludeReference(
-    std::string const& path,
-    cmOutputConverter::OutputFormat format = cmOutputConverter::SHELL,
-    bool forceFullPaths = false);
-
   /** Called from command-line hook to clear dependencies.  */
   virtual void ClearDependencies(cmMakefile* /* mf */, bool /* verbose */) {}
 
@@ -557,6 +558,13 @@ public:
   cmProp GetRuleLauncher(cmGeneratorTarget* target, const std::string& prop);
 
 protected:
+  // The default implementation ignores the IncludePathStyle and always
+  // uses absolute paths.  A generator may override this to use relative
+  // paths in some cases.
+  virtual std::string ConvertToIncludeReference(
+    std::string const& path, IncludePathStyle pathStyle,
+    cmOutputConverter::OutputFormat format);
+
   //! put all the libraries for a target on into the given stream
   void OutputLinkLibraries(cmComputeLinkInformation* pcli,
                            cmLinkLineComputer* linkLineComputer,