install(TARGETS): Add FILE_SET mode

Source/cmInstallFileSetGenerator.h

@@ -0,0 +1,52 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#pragma once
+
+#include <iosfwd>
+#include <map>
+#include <string>
+#include <vector>
+
+#include "cmInstallGenerator.h"
+#include "cmListFileCache.h"
+#include "cmScriptGenerator.h"
+
+class cmGeneratorTarget;
+class cmFileSet;
+class cmLocalGenerator;
+
+class cmInstallFileSetGenerator : public cmInstallGenerator
+{
+public:
+  cmInstallFileSetGenerator(std::string targetName, cmFileSet* fileSet,
+                            std::string const& dest,
+                            std::string file_permissions,
+                            std::vector<std::string> const& configurations,
+                            std::string const& component, MessageLevel message,
+                            bool exclude_from_all, bool optional,
+                            cmListFileBacktrace backtrace);
+  ~cmInstallFileSetGenerator() override;
+
+  bool Compute(cmLocalGenerator* lg) override;
+
+  std::string GetDestination(std::string const& config) const;
+  std::string GetDestination() const { return this->Destination; }
+  bool GetOptional() const { return this->Optional; }
+  cmFileSet* GetFileSet() const { return this->FileSet; }
+  cmGeneratorTarget* GetTarget() const { return this->Target; }
+
+protected:
+  void GenerateScriptForConfig(std::ostream& os, const std::string& config,
+                               Indent indent) override;
+
+private:
+  std::string TargetName;
+  cmLocalGenerator* LocalGenerator;
+  cmFileSet* const FileSet;
+  std::string const FilePermissions;
+  bool const Optional;
+  cmGeneratorTarget* Target;
+
+  std::map<std::string, std::vector<std::string>> CalculateFilesPerDir(
+    const std::string& config) const;
+};