CMake/Source/cmAddCustomCommandCommand.h

/*============================================================================
  CMake - Cross Platform Makefile Generator
  Copyright 2000-2009 Kitware, Inc., Insight Software Consortium

  Distributed under the OSI-approved BSD License (the "License");
  see accompanying file Copyright.txt for details.

  This software is distributed WITHOUT ANY WARRANTY; without even the
  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the License for more information.
============================================================================*/
#ifndef cmAddCustomCommandCommand_h
#define cmAddCustomCommandCommand_h

#include "cmCommand.h"
#include "cmDocumentGeneratorExpressions.h"

/** \class cmAddCustomCommandCommand
 * \brief 
 *
 *  cmAddCustomCommandCommand defines a new command (rule) that can
 *  be executed within the build process
 *
 */

class cmAddCustomCommandCommand : public cmCommand
{
public:
  /**
   * This is a virtual constructor for the command.
   */
  virtual cmCommand* Clone() 
    {
    return new cmAddCustomCommandCommand;
    }

  /**
   * This is called when the command is first encountered in
   * the CMakeLists.txt file.
   */
  virtual bool InitialPass(std::vector<std::string> const& args,
                           cmExecutionStatus &status);

  /**
   * The name of the command as specified in CMakeList.txt.
   */
  virtual const char* GetName() const {return "add_custom_command";}
  
  /**
   * Succinct documentation.
   */
  virtual const char* GetTerseDocumentation() const
    {
    return "Add a custom build rule to the generated build system.";
    }
  
  /**
   * More documentation.
   */
  virtual const char* GetFullDocumentation() const
    {
    return
      "There are two main signatures for add_custom_command "
      "The first signature is for adding a custom command "
      "to produce an output.\n"
      "  add_custom_command(OUTPUT output1 [output2 ...]\n"
      "                     COMMAND command1 [ARGS] [args1...]\n"
      "                     [COMMAND command2 [ARGS] [args2...] ...]\n"
      "                     [MAIN_DEPENDENCY depend]\n"
      "                     [DEPENDS [depends...]]\n"
      "                     [IMPLICIT_DEPENDS <lang1> depend1 ...]\n"
      "                     [WORKING_DIRECTORY dir]\n"
      "                     [COMMENT comment] [VERBATIM] [APPEND])\n"
      "This defines a command to generate specified OUTPUT file(s).  "
      "A target created in the same directory (CMakeLists.txt file) that "
      "specifies any output of the custom command as a source file is given "
      "a rule to generate the file using the command at build time.  "
      "Do not list the output in more than one independent target that may "
      "build in parallel or the two instances of the rule may conflict "
      "(instead use add_custom_target to drive the command and make the "
      "other targets depend on that one).  "
      "If an output name is a relative path it will be interpreted "
      "relative to the build tree directory corresponding to the current "
      "source directory. "
      "Note that MAIN_DEPENDENCY is completely optional and is "
      "used as a suggestion to visual studio about where to hang the "
      "custom command. In makefile terms this creates a new target in the "
      "following form:\n"
      "  OUTPUT: MAIN_DEPENDENCY DEPENDS\n"
      "          COMMAND\n"
      "If more than one command is specified they will be executed in order. "
      "The optional ARGS argument is for backward compatibility and will be "
      "ignored.\n"
      "The second signature adds a custom command to a target "
      "such as a library or executable. This is useful for "
      "performing an operation before or after building the target. "
      "The command becomes part of the target and will only execute "
      "when the target itself is built.  If the target is already built,"
      " the command will not execute.\n"
      "  add_custom_command(TARGET target\n"
      "                     PRE_BUILD | PRE_LINK | POST_BUILD\n"
      "                     COMMAND command1 [ARGS] [args1...]\n"
      "                     [COMMAND command2 [ARGS] [args2...] ...]\n"
      "                     [WORKING_DIRECTORY dir]\n"
      "                     [COMMENT comment] [VERBATIM])\n"
      "This defines a new command that will be associated with "
      "building the specified target. When the command will "
      "happen is determined by which of the following is specified:\n"
      "  PRE_BUILD - run before all other dependencies\n"
      "  PRE_LINK - run after other dependencies\n"
      "  POST_BUILD - run after the target has been built\n"
      "Note that the PRE_BUILD option is only supported on Visual "
      "Studio 7 or later. For all other generators PRE_BUILD "
      "will be treated as PRE_LINK.\n"
      "If WORKING_DIRECTORY is specified the command will be executed "
      "in the directory given. "
      "If it is a relative path it will be interpreted relative to the "
      "build tree directory corresponding to the current source directory. "
      "If COMMENT is set, the value will be displayed as a "
      "message before the commands are executed at build time. "
      "If APPEND is specified the COMMAND and DEPENDS option values "
      "are appended to the custom command for the first output specified. "
      "There must have already been a previous call to this command with "
      "the same output. The COMMENT, WORKING_DIRECTORY, and MAIN_DEPENDENCY "
      "options are currently ignored when APPEND is given, "
      "but may be used in the future."
      "\n"
      "If VERBATIM is given then all arguments to the commands will be "
      "escaped properly for the build tool so that the invoked command "
      "receives each argument unchanged.  "
      "Note that one level of escapes is still used by the CMake language "
      "processor before add_custom_command even sees the arguments. "
      "Use of VERBATIM is recommended as it enables correct behavior. "
      "When VERBATIM is not given the behavior is platform specific because "
      "there is no protection of tool-specific special characters."
      "\n"
      "If the output of the custom command is not actually "
      "created as a file on disk it should be marked as SYMBOLIC with "
      "SET_SOURCE_FILES_PROPERTIES.\n"

      "The IMPLICIT_DEPENDS option requests scanning of implicit "
      "dependencies of an input file.  The language given specifies the "
      "programming language whose corresponding dependency scanner should "
      "be used.  Currently only C and CXX language scanners are supported. "
      "Dependencies discovered from the scanning are added to those of "
      "the custom command at build time.  Note that the IMPLICIT_DEPENDS "
      "option is currently supported only for Makefile generators and "
      "will be ignored by other generators."
      "\n"
      "If COMMAND specifies an executable target (created by "
      "ADD_EXECUTABLE) it will automatically be replaced by the location "
      "of the executable created at build time.  Additionally a "
      "target-level dependency will be added so that the executable target "
      "will be built before any target using this custom command.  However "
      "this does NOT add a file-level dependency that would cause the "
      "custom command to re-run whenever the executable is recompiled."
      "\n"
      "Arguments to COMMAND may use \"generator expressions\" with the "
      "syntax \"$<...>\".  "
      CM_DOCUMENT_COMMAND_GENERATOR_EXPRESSIONS
      "References to target names in generator expressions imply "
      "target-level dependencies, but NOT file-level dependencies.  "
      "List target names with the DEPENDS option to add file dependencies."
      "\n"
      "The DEPENDS option specifies files on which the command depends.  "
      "If any dependency is an OUTPUT of another custom command in the "
      "same directory (CMakeLists.txt file) CMake automatically brings the "
      "other custom command into the target in which this command is built.  "
      "If DEPENDS is not specified the command will run whenever the OUTPUT "
      "is missing; if the command does not actually create the OUTPUT then "
      "the rule will always run.  "
      "If DEPENDS specifies any target (created by an ADD_* command) "
      "a target-level dependency is created to make sure the target is "
      "built before any target using this custom command.  Additionally, "
      "if the target is an executable or library a file-level dependency "
      "is created to cause the custom command to re-run whenever the target "
      "is recompiled.\n"
      ;
    }
  
  cmTypeMacro(cmAddCustomCommandCommand, cmCommand);
protected:
  bool CheckOutputs(const std::vector<std::string>& outputs);
};


#endif