Enhance FindFFmpeg.cmake

- Add fallback component version parsing from the individual <includedir>/<libname>/version.h headers - Switch to FFmpeg_<component>_<property> variable names, standard for CMake component variables - No longer probe for non-requested components - Use HANDLE_COMPONENT in find_package_handle_standard_args - Parse, export overall FFmpeg_VERSION from libavutil/ffversion.h
OpenShot · Jun 25, 2021 · 93fb2ee · 93fb2ee
1 parent 09eb807
commit 93fb2ee
Showing 1 changed file with 152 additions and 71 deletions.
diff --git a/cmake/Modules/FindFFmpeg.cmake b/cmake/Modules/FindFFmpeg.cmake
@@ -34,21 +34,23 @@ This module defines the following variables:
 
 ::
 
-  FFMPEG_FOUND         - System has the all required components.
-  FFMPEG_INCLUDE_DIRS  - Include directory necessary for using the required components headers.
-  FFMPEG_LIBRARIES     - Link these to use the required ffmpeg components.
-  FFMPEG_DEFINITIONS   - Compiler switches required for using the required ffmpeg components.
+  FFmpeg_FOUND         - System has the all required components.
+  FFmpeg_INCLUDE_DIRS  - Include directory necessary for using the required components headers.
+  FFmpeg_LIBRARIES     - Link these to use the required ffmpeg components.
+  FFmpeg_DEFINITIONS   - Compiler switches required for using the required ffmpeg components.
+  FFmpeg_VERSION       - The FFmpeg package version found.
 
-For each component, ``<component>_FOUND`` will be set if the component is available.
- 
-For each ``<component>_FOUND``,  the following variables will be defined:
+For each component, ``FFmpeg_<component>_FOUND`` will be set if the component is available.
+
+For each ``FFmpeg_<component>_FOUND``,  the following variables will be defined:
 
 ::
 
-  <component>_INCLUDE_DIRS - Include directory necessary for using the <component> headers
-  <component>_LIBRARIES    - Link these to use <component>
-  <component>_DEFINITIONS  - Compiler switches required for using <component>
-  <component>_VERSION      - The components version
+  FFmpeg_<component>_INCLUDE_DIRS - Include directory necessary for using the
+                                    <component> headers
+  FFmpeg_<component>_LIBRARIES    - Link these to use <component>
+  FFmpeg_<component>_DEFINITIONS  - Compiler switches required for <component>
+  FFmpeg_<component>_VERSION      - The components version
 
 Backwards compatibility
 ^^^^^^^^^^^^^^^^^^^^^^^
@@ -57,10 +59,20 @@ For compatibility with previous versions of this module, uppercase names
 for FFmpeg and for all components are also recognized, and all-uppercase
 versions of the cache variables are also created.
 
+Revision history
+^^^^^^^^^^^^^^^^
+ca. 2019   - Create CMake targets for discovered components
+2019-06-25 - No longer probe for non-requested components
+           - Added fallback version.h parsing for components, when
+             pkgconfig is missing
+           - Added parsing of libavutil/ffversion.h for FFmpeg_VERSION
+           - Adopt standard FFmpeg_<component>_<property> variable names
+           - Switch to full signature for FPHSA, use HANDLE_COMPONENTS
+
 Copyright (c) 2006, Matthias Kretz, <kretz@kde.org>
 Copyright (c) 2008, Alexander Neundorf, <neundorf@kde.org>
 Copyright (c) 2011, Michael Jansen, <kde@michael-jansen.biz>
-Copyright (c) 2019, FeRD (Frank Dana) <ferdnyc@gmail.com>
+Copyright (c) 2019-2021, FeRD (Frank Dana) <ferdnyc@gmail.com>
 
 Redistribution and use is allowed according to the terms of the BSD license.
 For details see the accompanying COPYING-CMAKE-SCRIPTS file.
@@ -84,16 +96,44 @@ endif ()
 # Marks the given component as found if both *_LIBRARIES AND *_INCLUDE_DIRS is present.
 #
 macro(set_component_found _component )
-  if (${_component}_LIBRARIES AND ${_component}_INCLUDE_DIRS)
+  if (FFmpeg_${_component}_LIBRARIES AND FFmpeg_${_component}_INCLUDE_DIRS)
     # message(STATUS "FFmpeg - ${_component} found.")
-    set(${_component}_FOUND TRUE)
+    set(FFmpeg_${_component}_FOUND TRUE)
   else ()
     if (NOT FFmpeg_FIND_QUIETLY AND NOT FFMPEG_FIND_QUIETLY)
       message(STATUS "FFmpeg - ${_component} not found.")
     endif ()
   endif ()
 endmacro()
 
+#
+### Macro: parse_lib_version
+#
+# Reads the file '${_pkgconfig}/version.h' in the component's _INCLUDE_DIR,
+# and parses #define statements for COMPONENT_VERSION_(MAJOR|MINOR|PATCH)
+# into a dotted string ${_component}_VERSION.
+#
+# Needed if the version is not supplied via pkgconfig's PC_${_component}_VERSION
+macro(parse_lib_version _component _libname )
+  set(_version_h "${FFmpeg_${_component}_INCLUDE_DIRS}/${_libname}/version.h")
+  if(EXISTS "${_version_h}")
+    #message(STATUS "Parsing ${_component} version from ${_version_h}")
+    string(TOUPPER "${_libname}" _prefix)
+    set(_parts)
+    foreach(_lvl MAJOR MINOR MICRO)
+      file(STRINGS "${_version_h}" _lvl_version
+      REGEX "^[ \t]*#define[ \t]+${_prefix}_VERSION_${_lvl}[ \t]+[0-9]+[ \t]*$")
+      string(REGEX REPLACE
+        "^.*${_prefix}_VERSION_${_lvl}[ \t]+([0-9]+)[ \t]*$"
+        "\\1"
+        _lvl_match "${_lvl_version}")
+      list(APPEND _parts "${_lvl_match}")
+    endforeach()
+    list(JOIN _parts "." FFmpeg_${_component}_VERSION)
+    message(STATUS "Found ${_component} version: ${FFmpeg_${_component}_VERSION}")
+  endif()
+endmacro()
+
 #
 ### Macro: find_component
 #
@@ -109,9 +149,9 @@ macro(find_component _component _pkgconfig _library _header)
     if (PKG_CONFIG_FOUND)
       pkg_check_modules(PC_${_component} ${_pkgconfig})
     endif ()
-  endif (NOT WIN32)
+  endif()
 
-  find_path(${_component}_INCLUDE_DIRS ${_header}
+  find_path(FFmpeg_${_component}_INCLUDE_DIRS ${_header}
     HINTS
     /opt/
     /opt/include/
@@ -123,7 +163,7 @@ macro(find_component _component _pkgconfig _library _header)
     ffmpeg
     )
 
-  find_library(${_component}_LIBRARIES NAMES ${_library}
+  find_library(FFmpeg_${_component}_LIBRARIES NAMES ${_library}
     HINTS
     ${PC_${_component}_LIBDIR}
     ${PC_${_component}_LIBRARY_DIRS}
@@ -132,56 +172,86 @@ macro(find_component _component _pkgconfig _library _header)
     $ENV{FFMPEGDIR}/bin/
     )
 
-  set(${_component}_DEFINITIONS  ${PC_${_component}_CFLAGS_OTHER} CACHE STRING "The ${_component} CFLAGS.")
-  set(${_component}_VERSION      ${PC_${_component}_VERSION}      CACHE STRING "The ${_component} version number.")
+  set(FFmpeg_${_component}_DEFINITIONS  ${PC_${_component}_CFLAGS_OTHER} CACHE STRING "The ${_component} CFLAGS.")
+
+  # Take version from PkgConfig, or parse from its version.h header
+  if (PC_${_component}_VERSION)
+    set(FFmpeg_${_component}_VERSION ${PC_${_component}_VERSION})
+  else()
+    parse_lib_version(${_component} ${_pkgconfig})
+  endif()
+
+  set(FFmpeg_${_component}_VERSION ${FFmpeg_${_component}_VERSION} CACHE STRING "The ${_component} version number.")
 
   set_component_found(${_component})
 
   mark_as_advanced(
-    ${_component}_INCLUDE_DIRS
-    ${_component}_LIBRARIES
-    ${_component}_DEFINITIONS
-    ${_component}_VERSION
+    FFmpeg_${_component}_INCLUDE_DIRS
+    FFmpeg_${_component}_LIBRARIES
+    FFmpeg_${_component}_DEFINITIONS
+    FFmpeg_${_component}_VERSION
     )
 
 endmacro()
 
+#
+### Macro: parse_ff_version
+#
+# Read the libavutil/ffversion.h file and extract the definition
+# for FFMPEG_VERSION, to use as our version string.
+macro (parse_ff_version)
+  set(_header "${FFmpeg_avutil_INCLUDE_DIRS}/libavutil/ffversion.h")
+  if(EXISTS "${_header}")
+    #message(STATUS "Parsing ffmpeg version from ${_header}")
+    file(STRINGS "${_header}" _version_def
+    REGEX "^#define[ \t]+FFMPEG_VERSION[ \t]+\".*\"[ \t]*$")
+    string(REGEX REPLACE
+      "^.*FFMPEG_VERSION[ \t]+\"(.*)\".*$"
+      "\\1"
+      FFmpeg_VERSION "${_version_def}")
+    #message(STATUS "Found FFmpeg version: ${FFmpeg_VERSION}")
+  endif()
+endmacro()
 
-# Check for cached results. If there are skip the costly part.
-if (NOT FFmpeg_LIBRARIES)
-
-  # Check for all possible component.
-  find_component(avcodec    libavcodec    avcodec  libavcodec/avcodec.h)
-  find_component(avdevice   libavdevice   avdevice libavdevice/avdevice.h)
-  find_component(avformat   libavformat   avformat libavformat/avformat.h)
-  find_component(avfilter   libavfilter   avfilter libavfilter/avfilter.h)
-  find_component(avutil     libavutil     avutil   libavutil/avutil.h)
-  find_component(postproc   libpostproc   postproc libpostproc/postprocess.h)
-  find_component(swscale    libswscale    swscale  libswscale/swscale.h)
-  find_component(swresample libswresample swresample libswresample/swresample.h)
-  find_component(avresample libavresample avresample libavresample/avresample.h)
-else()
-  # Just set the noncached _FOUND vars for the components.
-  foreach(_component ${FFmpeg_ALL_COMPONENTS})
-    set_component_found(${_component})
-  endforeach ()
-endif()
-
-# Check if the requested components were found and add their stuff to the FFmpeg_* vars.
-foreach (_component ${FFmpeg_FIND_COMPONENTS})
+# Configs for all possible component.
+set(avcodec_params    libavcodec    avcodec  libavcodec/avcodec.h)
+set(avdevice_params   libavdevice   avdevice libavdevice/avdevice.h)
+set(avformat_params   libavformat   avformat libavformat/avformat.h)
+set(avfilter_params   libavfilter   avfilter libavfilter/avfilter.h)
+set(avutil_params     libavutil     avutil   libavutil/avutil.h)
+set(postproc_params   libpostproc   postproc libpostproc/postprocess.h)
+set(swscale_params    libswscale    swscale  libswscale/swscale.h)
+set(swresample_params libswresample swresample libswresample/swresample.h)
+set(avresample_params libavresample avresample libavresample/avresample.h)
+
+# Gather configs for each requested component
+foreach(_component ${FFmpeg_FIND_COMPONENTS})
   string(TOLOWER "${_component}" _component)
-  if (${_component}_FOUND)
+  # Only probe if not already _FOUND (expensive)
+  if (NOT FFmpeg_${_component}_FOUND)
+    find_component(${_component} ${${_component}_params})
+  endif()
+
+  # Add the component's configs to the FFmpeg_* variables
+  if (FFmpeg_${_component}_FOUND)
     # message(STATUS "Requested component ${_component} present.")
-    set(FFmpeg_LIBRARIES   ${FFmpeg_LIBRARIES}   ${${_component}_LIBRARIES})
-    set(FFmpeg_DEFINITIONS ${FFmpeg_DEFINITIONS} ${${_component}_DEFINITIONS})
-    list(APPEND FFmpeg_INCLUDE_DIRS ${${_component}_INCLUDE_DIRS})
+    set(FFmpeg_LIBRARIES   ${FFmpeg_LIBRARIES}   ${FFmpeg_${_component}_LIBRARIES})
+    set(FFmpeg_DEFINITIONS ${FFmpeg_DEFINITIONS} ${FFmpeg_${_component}_DEFINITIONS})
+    list(APPEND FFmpeg_INCLUDE_DIRS ${FFmpeg_${_component}_INCLUDE_DIRS})
   else ()
     # message(STATUS "Requested component ${_component} missing.")
   endif ()
-endforeach ()
+endforeach()
+
+# Make sure we've probed for avutil
+if (NOT FFmpeg_avutil_FOUND)
+  find_component(avutil libavutil avutil libavutil/avutil.h)
+endif()
+# Get the overall FFmpeg version from libavutil/ffversion.h
+parse_ff_version()
 
 # Build the result lists with duplicates removed, in case of repeated
-# invocations.
+# invocations or component redundancy.
 if (FFmpeg_INCLUDE_DIRS)
   list(REMOVE_DUPLICATES FFmpeg_INCLUDE_DIRS)
 endif()
@@ -196,57 +266,68 @@ endif ()
 set(FFmpeg_INCLUDE_DIRS ${FFmpeg_INCLUDE_DIRS} CACHE STRING "The FFmpeg include directories." FORCE)
 set(FFmpeg_LIBRARIES    ${FFmpeg_LIBRARIES}    CACHE STRING "The FFmpeg libraries." FORCE)
 set(FFmpeg_DEFINITIONS  ${FFmpeg_DEFINITIONS}  CACHE STRING "The FFmpeg cflags." FORCE)
+set(FFmpeg_VERSION      ${FFmpeg_VERSION}      CACHE STRING "The overall FFmpeg version.")
 
-mark_as_advanced(FFmpeg_INCLUDE_DIRS
+mark_as_advanced(
+  FFmpeg_INCLUDE_DIRS
   FFmpeg_LIBRARIES
-  FFmpeg_DEFINITIONS)
+  FFmpeg_DEFINITIONS
+  FFmpeg_VERSION
+)
 
 # Backwards compatibility
-foreach(_suffix INCLUDE_DIRS LIBRARIES DEFINITIONS)
+foreach(_suffix INCLUDE_DIRS LIBRARIES DEFINITIONS VERSION)
   get_property(_help CACHE FFmpeg_${_suffix} PROPERTY HELPSTRING)
   set(FFMPEG_${_suffix} ${FFmpeg_${_suffix}} CACHE STRING "${_help}" FORCE)
   mark_as_advanced(FFMPEG_${_suffix})
 endforeach()
 foreach(_component ${FFmpeg_ALL_COMPONENTS})
-  if(${_component}_FOUND)
+  if(FFmpeg_${_component}_FOUND)
     string(TOUPPER "${_component}" _uc_component)
-    set(${_uc_component}_FOUND TRUE)
+    set(FFMPEG_${_uc_component}_FOUND TRUE)
     foreach(_suffix INCLUDE_DIRS LIBRARIES DEFINITIONS VERSION)
-      get_property(_help CACHE ${_component}_${_suffix} PROPERTY HELPSTRING)
-      set(${_uc_component}_${_suffix} ${${_component}_${_suffix}} CACHE STRING "${_help}" FORCE)
-      mark_as_advanced(${_uc_component}_${_suffix})
+      get_property(_help CACHE FFmpeg_${_component}_${_suffix} PROPERTY HELPSTRING)
+      set(FFMPEG_${_uc_component}_${_suffix} ${FFmpeg_${_component}_${_suffix}} CACHE STRING "${_help}" FORCE)
+      mark_as_advanced(FFMPEG_${_uc_component}_${_suffix})
     endforeach()
   endif()
 endforeach()
 
 # Compile the list of required vars
 set(_FFmpeg_REQUIRED_VARS FFmpeg_LIBRARIES FFmpeg_INCLUDE_DIRS)
-foreach (_component ${FFmpeg_FIND_COMPONENTS})
-  list(APPEND _FFmpeg_REQUIRED_VARS
-    ${_component}_LIBRARIES
-    ${_component}_INCLUDE_DIRS)
-endforeach ()
+# XXX: HANDLE_COMPONENTS should take care of this, maybe? -FeRD
+# foreach (_component ${FFmpeg_FIND_COMPONENTS})
+#   list(APPEND _FFmpeg_REQUIRED_VARS
+#     FFmpeg_${_component}_LIBRARIES
+#     FFmpeg_${_component}_INCLUDE_DIRS)
+# endforeach ()
 
 # Give a nice error message if some of the required vars are missing.
-find_package_handle_standard_args(FFmpeg DEFAULT_MSG ${_FFmpeg_REQUIRED_VARS})
+find_package_handle_standard_args(FFmpeg
+  REQUIRED_VARS ${_FFmpeg_REQUIRED_VARS}
+  VERSION_VAR FFmpeg_VERSION
+  HANDLE_COMPONENTS
+)
 
 # Export targets for each found component
-foreach (_component ${FFmpeg_ALL_COMPONENTS})
+foreach (_component ${FFmpeg_FIND_COMPONENTS})
 
-  if(${_component}_FOUND)
-    # message(STATUS "Creating IMPORTED target FFmpeg::${_component}")
+  if(FFmpeg_${_component}_FOUND)
+    #message(STATUS "Creating IMPORTED target FFmpeg::${_component}")
 
     if(NOT TARGET FFmpeg::${_component})
       add_library(FFmpeg::${_component} UNKNOWN IMPORTED)
 
       set_target_properties(FFmpeg::${_component} PROPERTIES
-        INTERFACE_INCLUDE_DIRECTORIES "${${_component}_INCLUDE_DIRS}")
+        INTERFACE_INCLUDE_DIRECTORIES
+          "${FFmpeg_${_component}_INCLUDE_DIRS}")
 
       set_property(TARGET FFmpeg::${_component} APPEND PROPERTY
-        INTERFACE_COMPILE_DEFINITIONS "${${_component}_DEFINITIONS}")
+        INTERFACE_COMPILE_DEFINITIONS
+          "${FFmpeg_${_component}_DEFINITIONS}")
 
       set_property(TARGET FFmpeg::${_component} APPEND PROPERTY
-        IMPORTED_LOCATION "${${_component}_LIBRARIES}")
+        IMPORTED_LOCATION "${FFmpeg_${_component}_LIBRARIES}")
     endif()
 
   endif()