[libcamera-devel] [PATCH] meson: Rework automatic pipeline selection

[Kieran Bingham]

The supported pipelines are listed in three places: the
meson_options.txt file, the defined array when a user selects
-Dpipelines="all", and arrays defined when the default
-Dpipelines="auto" is selected.

This can be hard to maintain and error prone.

Rework the definition of pipeline selection to a single table within the
meson.build to reduce duplication within this file. The new table
specifies the architecture(s) that the pipeline handler supports and
is iterated to handle the special cases for 'all', 'auto' and 'test'.

The current behaviour such that 'all' takes precedence over 'auto' is
maintained, and 'test' is now extended such that additional test
pipeline handlers can easily be introduced.

The existing implementation defines the i.MX8-ISI and RKISP1 pipeline
handlers as only supported by 'aarch64'. This conversion changes the
behaviour such that those pipeline handlers are now supported on both
'arm' and 'aarch64' as each of those platforms could support a 32-bit
ARM build.

Suggested-by: Javier Martinez Canillas <javierm at redhat.com>
Reviewed-by: Javier Martinez Canillas <javierm at redhat.com>
Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
 meson.build | 54 +++++++++++++++++++++++++++++------------------------
 1 file changed, 30 insertions(+), 24 deletions(-)

diff --git a/meson.build b/meson.build
index e86673dd5c0c..c35376e1e97b 100644
--- a/meson.build
+++ b/meson.build
@@ -164,38 +164,44 @@ liblttng = dependency('lttng-ust', required : get_option('tracing'))
 # are enabled.
 pipelines = get_option('pipelines')
 
+arch_arm = ['arm', 'aarch64']
+arch_x86 = ['x86', 'x86_64']
+pipes_support = {
+  'imx8-isi':     arch_arm,
+  'ipu3':         arch_x86,
+  'raspberrypi':  arch_arm,
+  'rkisp1':       arch_arm,
+  'simple':       arch_arm,
+  'uvcvideo':     ['any'],
+  'vimc':         ['test'],
+}
+
 if pipelines.contains('all')
-    pipelines = [
-        'imx8-isi',
-        'ipu3',
-        'raspberrypi',
-        'rkisp1',
-        'simple',
-        'uvcvideo',
-        'vimc',
-    ]
+    pipelines = []
+    foreach pipe, archs : pipes_support
+        pipelines += pipe
+    endforeach
 endif
 
 if pipelines.contains('auto')
     host_cpu = host_machine.cpu_family()
     pipelines = []
-    if host_cpu == 'x86' or host_cpu == 'x86_64'
-        pipelines += ['ipu3']
-    elif host_cpu == 'aarch64'
-        pipelines += ['imx8-isi', 'rkisp1']
-    endif
-
-    if host_cpu == 'arm' or host_cpu == 'aarch64'
-        pipelines += ['raspberrypi', 'simple']
-    endif
-
-    # Always include the uvcvideo pipeline handler.
-    pipelines += ['uvcvideo']
+    foreach pipe, archs : pipes_support
+        if host_cpu in archs or 'any' in archs
+            message('Auto-enabling ' + pipe + ' pipeline handler')
+            pipelines += pipe
+        endif
+    endforeach
 endif
 
-if get_option('test') and 'vimc' not in pipelines
-    message('Enabling vimc pipeline handler to support tests')
-    pipelines += ['vimc']
+if get_option('test')
+    foreach pipe, archs : pipes_support
+        if 'test' in archs and pipe not in pipelines
+            message('Enabling ' + pipe + ' pipeline handler for tests')
+            pipelines += pipe
+        endif
+    endforeach
 endif
 
 # Utilities are parsed first to provide support for other components.
-- 
2.34.1