Compute resource directory on startup

Add a findResourceDir function to locate resources relative to the
executable location at the start of main and a getResourceDir
function to lookup the result later.

6 files changed, 132 insertions, 1 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 37a0d1b..81a2151 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -35,6 +35,8 @@ endif()
 
 set(KWSYS_NAMESPACE cxsys)
 set(KWSYS_USE_Encoding 1)
+set(KWSYS_USE_RegularExpression 1)
+set(KWSYS_USE_SystemTools 1)
 set(KWSYS_HEADER_ROOT ${CastXML_BINARY_DIR}/src)
 add_subdirectory(src/kwsys)
 include_directories(${KWSYS_HEADER_ROOT})
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index f497e4f..97e1a02 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -14,11 +14,23 @@
 # limitations under the License.
 #=============================================================================
 
+# Tell executables in the build tree where to find the source tree.
+configure_file(
+  "SourceDir.txt.in"
+  "${CastXML_BINARY_DIR}/CMakeFiles/castxmlSourceDir.txt" @ONLY
+  )
+
 llvm_map_components_to_libraries(llvm_libs native option bitreader)
 
-add_executable(castxml castxml.cxx)
+add_executable(castxml
+  castxml.cxx
+
+  Utils.cxx Utils.h
+  )
 target_link_libraries(castxml
   cxsys
   ${llvm_libs}
   )
+set_property(SOURCE Utils.cxx APPEND PROPERTY COMPILE_DEFINITIONS
+  "CASTXML_INSTALL_DATA_DIR=\"${CastXML_INSTALL_DATA_DIR}\"")
 install(TARGETS castxml DESTINATION ${CastXML_INSTALL_RUNTIME_DIR})
diff --git a/src/SourceDir.txt.in b/src/SourceDir.txt.in
new file mode 100644
index 0000000..a607cf7
--- /dev/null
+++ b/src/SourceDir.txt.in
@@ -0,0 +1 @@
+@CastXML_SOURCE_DIR@
diff --git a/src/Utils.cxx b/src/Utils.cxx
new file mode 100644
index 0000000..bc556e3
--- /dev/null
+++ b/src/Utils.cxx
@@ -0,0 +1,80 @@
+/*
+  Copyright Kitware, Inc.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+*/
+
+#include "Utils.h"
+
+#include <cxsys/SystemTools.hxx>
+#include <llvm/Support/FileSystem.h>
+#include <fstream>
+
+static std::string castxmlResourceDir;
+
+//----------------------------------------------------------------------------
+static std::string GetMainExecutable(const char* argv0)
+{
+  return llvm::sys::fs::getMainExecutable
+    (argv0, (void*)(intptr_t)GetMainExecutable);
+}
+
+//----------------------------------------------------------------------------
+static bool tryBuildDir(std::string const& dir)
+{
+  // Build tree has
+  //   <build>/CMakeFiles/castxmlSourceDir.txt
+  std::string src_dir_txt = dir + "/CMakeFiles/castxmlSourceDir.txt";
+  std::ifstream src_fin(src_dir_txt.c_str());
+  std::string src_dir;
+  if(src_fin && cxsys::SystemTools::GetLineFromStream(src_fin, src_dir) &&
+     cxsys::SystemTools::FileIsDirectory(src_dir.c_str())) {
+    castxmlResourceDir = src_dir + "/share/castxml";
+    return true;
+  }
+  return false;
+}
+
+//----------------------------------------------------------------------------
+bool findResourceDir(const char* argv0, std::ostream& error)
+{
+  std::string exe = GetMainExecutable(argv0);
+  if(!cxsys::SystemTools::FileIsFullPath(exe.c_str())) {
+    error << "error: unable to locate " << argv0 << "\n";
+    return false;
+  }
+  std::string exe_dir = cxsys::SystemTools::GetFilenamePath(exe);
+
+  // Install tree has
+  //   <prefix>/bin/castxml
+  //   <prefix>/<CASTXML_INSTALL_DATA_DIR>
+  std::string dir = cxsys::SystemTools::GetFilenamePath(exe_dir);
+  castxmlResourceDir = dir + "/" + CASTXML_INSTALL_DATA_DIR;
+  if(!cxsys::SystemTools::FileIsDirectory(castxmlResourceDir.c_str())) {
+    // Build tree has
+    //   <build>/bin[/<config>]/castxml
+    if(!tryBuildDir(dir) &&
+       !tryBuildDir(cxsys::SystemTools::GetFilenamePath(dir))) {
+      error << "Unable to locate resources for " << exe << "\n";
+      return false;
+    }
+  }
+
+  return true;
+}
+
+//----------------------------------------------------------------------------
+std::string getResourceDir()
+{
+  return castxmlResourceDir;
+}
diff --git a/src/Utils.h b/src/Utils.h
new file mode 100644
index 0000000..7ea3a41
--- /dev/null
+++ b/src/Utils.h
@@ -0,0 +1,30 @@
+/*
+  Copyright Kitware, Inc.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+*/
+#ifndef CASTXML_UTILS_H
+#define CASTXML_UTILS_H
+
+#include <cxsys/Configure.hxx>
+#include <string>
+
+/// findResources - Call from main() to find resources
+/// relative to the executable.  On success returns true.
+/// On failure returns false and stores a message in the stream.
+bool findResourceDir(const char* argv0, std::ostream& error);
+
+/// getResourceDir - Get resource directory found at startup
+std::string getResourceDir();
+
+#endif // CASTXML_UTILS_H
diff --git a/src/castxml.cxx b/src/castxml.cxx
index dacbe83..ee303ab 100644
--- a/src/castxml.cxx
+++ b/src/castxml.cxx
@@ -14,7 +14,10 @@
   limitations under the License.
 */
 
+#include "Utils.h"
+
 #include <cxsys/Encoding.hxx>
+#include <iostream>
 
 //----------------------------------------------------------------------------
 int main(int argc, const char* const * argv)
@@ -23,6 +26,9 @@ int main(int argc, const char* const * argv)
     cxsys::Encoding::CommandLineArguments::Main(argc, argv);
   argc = args.argc();
   argv = args.argv();
+  if(!findResourceDir(argv[0], std::cerr)) {
+    return 1;
+  }
   (void)argc;
   (void)argv;
   return 0;