android: Split HAL to its own shared library

The libcamera Android HAL implementation should not be an integral part
of libcamera, but a support library that utilises the libcamera public
API.

Move the implementation to its own distinct library.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/android/cros/meson.build

@@ -15,4 +15,4 @@ cros_hal_info = static_library('cros_hal_info',
                                include_directories : [android_includes,
                                                       libcamera_includes])
 
-libcamera_objects += cros_hal_info.extract_objects('camera3_hal.cpp')
+android_objects += cros_hal_info.extract_objects('camera3_hal.cpp')

src/android/meson.build

@@ -4,6 +4,7 @@ android_deps = [
     dependency('libexif', required : get_option('android')),
     dependency('libjpeg', required : get_option('android')),
     dependency('yaml-0.1', required : get_option('android')),
+    libcamera_dep,
 ]
 
 android_enabled = true
@@ -36,8 +37,11 @@ endif
 
 android_deps += [libyuv_dep]
 
+android_cpp_args = []
+android_objects = []
+
 if get_option('android_platform') == 'cros'
-   libcamera_cpp_args += [ '-DOS_CHROMEOS']
+    android_cpp_args += ['-DOS_CHROMEOS']
 endif
 
 subdir('cros')
@@ -69,3 +73,13 @@ android_camera_metadata = static_library('camera_metadata',
                                          android_camera_metadata_sources,
                                          c_args : '-Wno-shadow',
                                          include_directories : android_includes)
+
+libcamera_hal = shared_library('libcamera-hal',
+                               android_hal_sources,
+                               name_prefix : '',
+                               link_with : android_camera_metadata,
+                               install : true,
+                               cpp_args : android_cpp_args,
+                               objects : android_objects,
+                               include_directories : android_includes,
+                               dependencies : android_deps)

src/libcamera/meson.build

@@ -130,16 +130,6 @@ libcamera_deps = [
     dependency('threads'),
 ]
 
-libcamera_link_with = []
-
-if android_enabled
-    libcamera_sources += android_hal_sources
-    includes += android_includes
-    libcamera_link_with += android_camera_metadata
-
-    libcamera_deps += android_deps
-endif
-
 # We add '/' to the build_rpath as a 'safe' path to act as a boolean flag.
 # The build_rpath is stripped at install time by meson, so we determine at
 # runtime if the library is running from an installed location by checking
@@ -148,10 +138,7 @@ endif
 libcamera = shared_library('camera',
                            libcamera_sources,
                            install : true,
-                           link_with : libcamera_link_with,
-                           cpp_args : libcamera_cpp_args,
                            include_directories : includes,
-                           objects : libcamera_objects,
                            build_rpath : '/',
                            dependencies : libcamera_deps)
 

src/meson.build

@@ -25,14 +25,10 @@ else
     ipa_sign_module = false
 endif
 
-libcamera_cpp_args = []
-libcamera_objects = []
-
-# The 'android' subdir must be processed first, and the build targets
-# are included directly into the libcamera library when this is enabled.
-subdir('android')
-
+# libcamera must be built first as a dependency to the other components.
 subdir('libcamera')
+
+subdir('android')
 subdir('ipa')
 
 subdir('lc-compliance')