export: Implement EXPORT subcommand (#9822)

Teach the export command to handle export sets defined by invocations
of install(TARGETS ... EXPORT foo).  This makes maintenance of targets
exported to both the build tree and install tree trivial.

16 files changed, 212 insertions, 74 deletions

diff --git a/Help/command/export.rst b/Help/command/export.rst
index c293340011..6b83587364 100644
--- a/Help/command/export.rst
+++ b/Help/command/export.rst
@@ -5,8 +5,7 @@ Export targets from the build tree for use by outside projects.
 
 ::
 
-  export(TARGETS [target1 [target2 [...]]] [NAMESPACE <namespace>]
-         [APPEND] FILE <filename> [EXPORT_LINK_INTERFACE_LIBRARIES])
+  export(EXPORT <export-name> [NAMESPACE <namespace>] [FILE <filename>])
 
 Create a file <filename> that may be included by outside projects to
 import targets from the current project's build tree.  This is useful
@@ -14,14 +13,10 @@ during cross-compiling to build utility executables that can run on
 the host platform in one project and then import them into another
 project being compiled for the target platform.  If the NAMESPACE
 option is given the <namespace> string will be prepended to all target
-names written to the file.  If the APPEND option is given the
-generated code will be appended to the file instead of overwriting it.
-The EXPORT_LINK_INTERFACE_LIBRARIES keyword, if present, causes the
-contents of the properties matching
-``(IMPORTED_)?LINK_INTERFACE_LIBRARIES(_<CONFIG>)?`` to be exported, when
-policy CMP0022 is NEW.  If a library target is included in the export
-but a target to which it links is not included the behavior is
-unspecified.
+names written to the file.
+
+Target installations are associated with the export <export-name>
+using the ``EXPORT`` option of the :command:`install(TARGETS)` command.
 
 The file created by this command is specific to the build tree and
 should never be installed.  See the install(EXPORT) command to export
@@ -32,6 +27,21 @@ same values as the final values of the input TARGETS.
 
 ::
 
+  export(TARGETS [target1 [target2 [...]]] [NAMESPACE <namespace>]
+         [APPEND] FILE <filename> [EXPORT_LINK_INTERFACE_LIBRARIES])
+
+This signature is similar to the ``EXPORT`` signature, but targets are listed
+explicitly rather than specified as an export-name.  If the APPEND option is
+given the generated code will be appended to the file instead of overwriting it.
+The EXPORT_LINK_INTERFACE_LIBRARIES keyword, if present, causes the
+contents of the properties matching
+``(IMPORTED_)?LINK_INTERFACE_LIBRARIES(_<CONFIG>)?`` to be exported, when
+policy CMP0022 is NEW.  If a library target is included in the export
+but a target to which it links is not included the behavior is
+unspecified.
+
+::
+
   export(PACKAGE <name>)
 
 Store the current build directory in the CMake user package registry
diff --git a/Source/cmExportBuildFileGenerator.cxx b/Source/cmExportBuildFileGenerator.cxx
index c10f86f741..b669cd110b 100644
--- a/Source/cmExportBuildFileGenerator.cxx
+++ b/Source/cmExportBuildFileGenerator.cxx
@@ -13,11 +13,14 @@
 
 #include "cmLocalGenerator.h"
 #include "cmGlobalGenerator.h"
+#include "cmExportSet.h"
+#include "cmTargetExport.h"
 
 //----------------------------------------------------------------------------
 cmExportBuildFileGenerator::cmExportBuildFileGenerator()
 {
   this->Makefile = 0;
+  this->ExportSet = 0;
 }
 
 //----------------------------------------------------------------------------
@@ -26,9 +29,11 @@ bool cmExportBuildFileGenerator::GenerateMainFile(std::ostream& os)
   {
   std::string expectedTargets;
   std::string sep;
+  std::vector<std::string> targets;
+  this->GetTargets(targets);
   for(std::vector<std::string>::const_iterator
-        tei = this->Targets.begin();
-      tei != this->Targets.end(); ++tei)
+        tei = targets.begin();
+      tei != targets.end(); ++tei)
     {
     cmTarget *te = this->Makefile->FindTargetToUse(tei->c_str());
     expectedTargets += sep + this->Namespace + te->GetExportName();
@@ -153,6 +158,12 @@ cmExportBuildFileGenerator
 }
 
 //----------------------------------------------------------------------------
+void cmExportBuildFileGenerator::SetExportSet(cmExportSet *exportSet)
+{
+  this->ExportSet = exportSet;
+}
+
+//----------------------------------------------------------------------------
 void
 cmExportBuildFileGenerator
 ::SetImportLocationProperty(const char* config, std::string const& suffix,
@@ -232,6 +243,23 @@ cmExportBuildFileGenerator::HandleMissingTarget(
 }
 
 //----------------------------------------------------------------------------
+void cmExportBuildFileGenerator
+::GetTargets(std::vector<std::string> &targets) const
+{
+  if (this->ExportSet)
+    {
+    for(std::vector<cmTargetExport*>::const_iterator
+          tei = this->ExportSet->GetTargetExports()->begin();
+          tei != this->ExportSet->GetTargetExports()->end(); ++tei)
+      {
+      targets.push_back((*tei)->Target->GetName());
+      }
+    return;
+    }
+  targets = this->Targets;
+}
+
+//----------------------------------------------------------------------------
 std::vector<std::string>
 cmExportBuildFileGenerator
 ::FindNamespaces(cmMakefile* mf, const std::string& name)
@@ -246,8 +274,8 @@ cmExportBuildFileGenerator
       expIt = exportSets.begin(); expIt != exportSets.end(); ++expIt)
     {
     const cmExportBuildFileGenerator* exportSet = expIt->second;
-    std::vector<std::string> const& targets = exportSet->GetTargets();
-
+    std::vector<std::string> targets;
+    exportSet->GetTargets(targets);
     if (std::find(targets.begin(), targets.end(), name) != targets.end())
       {
       namespaces.push_back(exportSet->GetNamespace());
diff --git a/Source/cmExportBuildFileGenerator.h b/Source/cmExportBuildFileGenerator.h
index 2fbd98f66a..cea2099b7b 100644
--- a/Source/cmExportBuildFileGenerator.h
+++ b/Source/cmExportBuildFileGenerator.h
@@ -15,6 +15,8 @@
 #include "cmExportFileGenerator.h"
 #include "cmListFileCache.h"
 
+class cmExportSet;
+
 /** \class cmExportBuildFileGenerator
  * \brief Generate a file exporting targets from a build tree.
  *
@@ -32,11 +34,11 @@ public:
   /** Set the list of targets to export.  */
   void SetTargets(std::vector<std::string> const& targets)
     { this->Targets = targets; }
-  std::vector<std::string> const& GetTargets() const
-    { return this->Targets; }
+  void GetTargets(std::vector<std::string> &targets) const;
   void AppendTargets(std::vector<std::string> const& targets)
     { this->Targets.insert(this->Targets.end(),
       targets.begin(), targets.end()); }
+  void SetExportSet(cmExportSet*);
 
   /** Set whether to append generated code to the output file.  */
   void SetAppendMode(bool append) { this->AppendMode = append; }
@@ -75,6 +77,7 @@ protected:
   FindNamespaces(cmMakefile* mf, const std::string& name);
 
   std::vector<std::string> Targets;
+  cmExportSet *ExportSet;
   std::vector<cmTarget*> Exports;
   cmMakefile* Makefile;
   cmListFileBacktrace Backtrace;
diff --git a/Source/cmExportCommand.cxx b/Source/cmExportCommand.cxx
index 0a67ccf38a..b6bf870a0a 100644
--- a/Source/cmExportCommand.cxx
+++ b/Source/cmExportCommand.cxx
@@ -30,14 +30,12 @@ cmExportCommand::cmExportCommand()
 ,ArgumentGroup()
 ,Targets(&Helper, "TARGETS")
 ,Append(&Helper, "APPEND", &ArgumentGroup)
+,ExportSetName(&Helper, "EXPORT", &ArgumentGroup)
 ,Namespace(&Helper, "NAMESPACE", &ArgumentGroup)
 ,Filename(&Helper, "FILE", &ArgumentGroup)
 ,ExportOld(&Helper, "EXPORT_LINK_INTERFACE_LIBRARIES", &ArgumentGroup)
 {
-  // at first TARGETS
-  this->Targets.Follows(0);
-  // and after that the other options in any order
-  this->ArgumentGroup.Follows(&this->Targets);
+  this->ExportSet = 0;
 }
 
 
@@ -55,6 +53,16 @@ bool cmExportCommand
     {
     return this->HandlePackage(args);
     }
+  else if (args[0] == "EXPORT")
+    {
+    this->ExportSetName.Follows(0);
+    this->ArgumentGroup.Follows(&this->ExportSetName);
+    }
+  else
+    {
+    this->Targets.Follows(0);
+    this->ArgumentGroup.Follows(&this->Targets);
+    }
 
   std::vector<std::string> unknownArgs;
   this->Helper.Parse(&args, &unknownArgs);
@@ -65,31 +73,32 @@ bool cmExportCommand
     return false;
     }
 
-  if (this->Targets.WasFound() == false)
-    {
-    this->SetError("TARGETS option missing.");
-    return false;
-    }
-
+  std::string fname;
   if(!this->Filename.WasFound())
     {
-    this->SetError("FILE <filename> option missing.");
-    return false;
+    if (args[0] != "EXPORT")
+      {
+      this->SetError("FILE <filename> option missing.");
+      return false;
+      }
+    fname = this->ExportSetName.GetString() + ".cmake";
     }
-
-  // Make sure the file has a .cmake extension.
-  if(cmSystemTools::GetFilenameLastExtension(this->Filename.GetCString())
-     != ".cmake")
+  else
     {
-    cmOStringStream e;
-    e << "FILE option given filename \"" << this->Filename.GetString()
-      << "\" which does not have an extension of \".cmake\".\n";
-    this->SetError(e.str().c_str());
-    return false;
+    // Make sure the file has a .cmake extension.
+    if(cmSystemTools::GetFilenameLastExtension(this->Filename.GetCString())
+      != ".cmake")
+      {
+      cmOStringStream e;
+      e << "FILE option given filename \"" << this->Filename.GetString()
+        << "\" which does not have an extension of \".cmake\".\n";
+      this->SetError(e.str().c_str());
+      return false;
+      }
+    fname = this->Filename.GetString();
     }
 
   // Get the file to write.
-  std::string fname = this->Filename.GetString();
   if(cmSystemTools::FileIsFullPath(fname.c_str()))
     {
     if(!this->Makefile->CanIWriteThisFile(fname.c_str()))
@@ -104,57 +113,95 @@ bool cmExportCommand
   else
     {
     // Interpret relative paths with respect to the current build dir.
-    fname = this->Makefile->GetCurrentOutputDirectory();
-    fname += "/";
-    fname += this->Filename.GetString();
+    std::string dir = this->Makefile->GetCurrentOutputDirectory();
+    fname = dir + "/" + fname;
     }
 
-  for(std::vector<std::string>::const_iterator
-      currentTarget = this->Targets.GetVector().begin();
-      currentTarget != this->Targets.GetVector().end();
-      ++currentTarget)
+  std::vector<std::string> targets;
+
+  cmGlobalGenerator *gg = this->Makefile->GetLocalGenerator()
+                                        ->GetGlobalGenerator();
+
+  if(args[0] == "EXPORT")
     {
-    if (this->Makefile->IsAlias(currentTarget->c_str()))
+    if (this->Append.IsEnabled())
+      {
+      cmOStringStream e;
+      e << "EXPORT signature does not recognise the APPEND option.";
+      this->SetError(e.str().c_str());
+      return false;
+      }
+
+    if (this->ExportOld.IsEnabled())
       {
       cmOStringStream e;
-      e << "given ALIAS target \"" << *currentTarget
-        << "\" which may not be exported.";
+      e << "EXPORT signature does not recognise the "
+        "EXPORT_LINK_INTERFACE_LIBRARIES option.";
       this->SetError(e.str().c_str());
       return false;
       }
 
-    if(cmTarget* target =
-       this->Makefile->GetLocalGenerator()->
-       GetGlobalGenerator()->FindTarget(0, currentTarget->c_str()))
+    cmExportSetMap &setMap = gg->GetExportSets();
+    std::string setName = this->ExportSetName.GetString();
+    if (setMap.find(setName) == setMap.end())
       {
-      if(target->GetType() == cmTarget::OBJECT_LIBRARY)
+      cmOStringStream e;
+      e << "Export set \"" << setName << "\" not found.";
+      this->SetError(e.str().c_str());
+      return false;
+      }
+    this->ExportSet = setMap[setName];
+    }
+  else if (this->Targets.WasFound())
+    {
+    for(std::vector<std::string>::const_iterator
+        currentTarget = this->Targets.GetVector().begin();
+        currentTarget != this->Targets.GetVector().end();
+        ++currentTarget)
+      {
+      if (this->Makefile->IsAlias(currentTarget->c_str()))
         {
         cmOStringStream e;
-        e << "given OBJECT library \"" << *currentTarget
+        e << "given ALIAS target \"" << *currentTarget
           << "\" which may not be exported.";
         this->SetError(e.str().c_str());
         return false;
         }
+
+      if(cmTarget* target = gg->FindTarget(0, currentTarget->c_str()))
+        {
+        if(target->GetType() == cmTarget::OBJECT_LIBRARY)
+          {
+          cmOStringStream e;
+          e << "given OBJECT library \"" << *currentTarget
+            << "\" which may not be exported.";
+          this->SetError(e.str().c_str());
+          return false;
+          }
+        }
+      else
+        {
+        cmOStringStream e;
+        e << "given target \"" << *currentTarget
+          << "\" which is not built by this project.";
+        this->SetError(e.str().c_str());
+        return false;
+        }
+      targets.push_back(*currentTarget);
       }
-    else
+    if (this->Append.IsEnabled())
       {
-      cmOStringStream e;
-      e << "given target \"" << *currentTarget
-        << "\" which is not built by this project.";
-      this->SetError(e.str().c_str());
-      return false;
+      if (cmExportBuildFileGenerator *ebfg = gg->GetExportedTargetsFile(fname))
+        {
+        ebfg->AppendTargets(targets);
+        return true;
+        }
       }
     }
-
-  cmGlobalGenerator *gg = this->Makefile->GetLocalGenerator()
-                                        ->GetGlobalGenerator();
-  if (this->Append.IsEnabled())
+  else
     {
-    if (cmExportBuildFileGenerator *ebfg = gg->GetExportedTargetsFile(fname))
-      {
-      ebfg->AppendTargets(this->Targets.GetVector());
-      return true;
-      }
+    this->SetError("EXPORT or TARGETS specifier missing.");
+    return false;
     }
 
   // Setup export file generation.
@@ -162,7 +209,14 @@ bool cmExportCommand
   ebfg->SetExportFile(fname.c_str());
   ebfg->SetNamespace(this->Namespace.GetCString());
   ebfg->SetAppendMode(this->Append.IsEnabled());
-  ebfg->SetTargets(this->Targets.GetVector());
+  if (this->ExportSet)
+    {
+    ebfg->SetExportSet(this->ExportSet);
+    }
+  else
+    {
+    ebfg->SetTargets(targets);
+    }
   ebfg->SetMakefile(this->Makefile);
   ebfg->SetExportOld(this->ExportOld.IsEnabled());
 
diff --git a/Source/cmExportCommand.h b/Source/cmExportCommand.h
index ea7c3a309b..c0e445f8a6 100644
--- a/Source/cmExportCommand.h
+++ b/Source/cmExportCommand.h
@@ -15,6 +15,7 @@
 #include "cmCommand.h"
 
 class cmExportBuildFileGenerator;
+class cmExportSet;
 
 /** \class cmExportLibraryDependenciesCommand
  * \brief Add a test to the lists of tests to run.
@@ -52,10 +53,13 @@ private:
   cmCommandArgumentGroup ArgumentGroup;
   cmCAStringVector Targets;
   cmCAEnabler Append;
+  cmCAString ExportSetName;
   cmCAString Namespace;
   cmCAString Filename;
   cmCAEnabler ExportOld;
 
+  cmExportSet *ExportSet;
+
   friend class cmExportBuildFileGenerator;
   std::string ErrorMessage;
 
diff --git a/Tests/ExportImport/Export/Interface/CMakeLists.txt b/Tests/ExportImport/Export/Interface/CMakeLists.txt
index b71326249f..f400f1335c 100644
--- a/Tests/ExportImport/Export/Interface/CMakeLists.txt
+++ b/Tests/ExportImport/Export/Interface/CMakeLists.txt
@@ -23,11 +23,6 @@ set_property(TARGET sharedlib PROPERTY INTERFACE_COMPILE_DEFINITIONS "SHAREDLIB_
 add_library(sharediface INTERFACE)
 target_link_libraries(sharediface INTERFACE sharedlib)
 
-export(TARGETS sharediface sharedlib headeronly
-  NAMESPACE bld::
-  FILE ../ExportInterfaceBuildTree.cmake
-)
-
 install(TARGETS headeronly sharediface sharedlib
   EXPORT expInterface
   RUNTIME DESTINATION bin
@@ -47,3 +42,8 @@ install(FILES
 )
 
 install(EXPORT expInterface NAMESPACE exp:: DESTINATION lib/exp)
+
+export(EXPORT expInterface
+  NAMESPACE bld::
+  FILE ../ExportInterfaceBuildTree.cmake
+)
diff --git a/Tests/RunCMake/export/AppendExport-result.txt b/Tests/RunCMake/export/AppendExport-result.txt
new file mode 100644
index 0000000000..d00491fd7e
--- /dev/null
+++ b/Tests/RunCMake/export/AppendExport-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/export/AppendExport-stderr.txt b/Tests/RunCMake/export/AppendExport-stderr.txt
new file mode 100644
index 0000000000..6e385d495a
--- /dev/null
+++ b/Tests/RunCMake/export/AppendExport-stderr.txt
@@ -0,0 +1,4 @@
+CMake Error at AppendExport.cmake:8 \(export\):
+  export EXPORT signature does not recognise the APPEND option.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)
diff --git a/Tests/RunCMake/export/AppendExport.cmake b/Tests/RunCMake/export/AppendExport.cmake
new file mode 100644
index 0000000000..f36010b6ae
--- /dev/null
+++ b/Tests/RunCMake/export/AppendExport.cmake
@@ -0,0 +1,8 @@
+add_library(foo empty.cpp)
+export(TARGETS foo FILE "${CMAKE_CURRENT_BINARY_DIR}/foo.cmake")
+install(TARGETS foo EXPORT fooExport
+  RUNTIME DESTINATION bin
+  LIBRARY DESTINATION lib
+  ARCHIVE DESTINATION lib
+)
+export(EXPORT fooExport APPEND FILE "${CMAKE_CURRENT_BINARY_DIR}/foo.cmake")
diff --git a/Tests/RunCMake/export/NoExportSet-result.txt b/Tests/RunCMake/export/NoExportSet-result.txt
new file mode 100644
index 0000000000..d00491fd7e
--- /dev/null
+++ b/Tests/RunCMake/export/NoExportSet-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/export/NoExportSet-stderr.txt b/Tests/RunCMake/export/NoExportSet-stderr.txt
new file mode 100644
index 0000000000..9d27805e00
--- /dev/null
+++ b/Tests/RunCMake/export/NoExportSet-stderr.txt
@@ -0,0 +1,4 @@
+CMake Error at NoExportSet.cmake:2 \(export\):
+  export Export set "fooExport" not found.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)
diff --git a/Tests/RunCMake/export/NoExportSet.cmake b/Tests/RunCMake/export/NoExportSet.cmake
new file mode 100644
index 0000000000..72390e822a
--- /dev/null
+++ b/Tests/RunCMake/export/NoExportSet.cmake
@@ -0,0 +1,2 @@
+
+export(EXPORT fooExport)
diff --git a/Tests/RunCMake/export/OldIface-result.txt b/Tests/RunCMake/export/OldIface-result.txt
new file mode 100644
index 0000000000..d00491fd7e
--- /dev/null
+++ b/Tests/RunCMake/export/OldIface-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/export/OldIface-stderr.txt b/Tests/RunCMake/export/OldIface-stderr.txt
new file mode 100644
index 0000000000..afb4ae3ac6
--- /dev/null
+++ b/Tests/RunCMake/export/OldIface-stderr.txt
@@ -0,0 +1,5 @@
+CMake Error at OldIface.cmake:8 \(export\):
+  export EXPORT signature does not recognise the
+  EXPORT_LINK_INTERFACE_LIBRARIES option.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)
diff --git a/Tests/RunCMake/export/OldIface.cmake b/Tests/RunCMake/export/OldIface.cmake
new file mode 100644
index 0000000000..5fb8e259da
--- /dev/null
+++ b/Tests/RunCMake/export/OldIface.cmake
@@ -0,0 +1,10 @@
+add_library(foo empty.cpp)
+export(TARGETS foo FILE "${CMAKE_CURRENT_BINARY_DIR}/foo.cmake")
+install(TARGETS foo EXPORT fooExport
+  RUNTIME DESTINATION bin
+  LIBRARY DESTINATION lib
+  ARCHIVE DESTINATION lib
+)
+export(EXPORT fooExport
+  EXPORT_LINK_INTERFACE_LIBRARIES
+)
diff --git a/Tests/RunCMake/export/RunCMakeTest.cmake b/Tests/RunCMake/export/RunCMakeTest.cmake
index b8d3f275f6..4b04f18589 100644
--- a/Tests/RunCMake/export/RunCMakeTest.cmake
+++ b/Tests/RunCMake/export/RunCMakeTest.cmake
@@ -1,3 +1,6 @@
 include(RunCMake)
 
 run_cmake(TargetNotFound)
+run_cmake(AppendExport)
+run_cmake(OldIface)
+run_cmake(NoExportSet)