Add a SCons tool for nanopb protos.

This tool script is useful both for building the tests and also for use in other applications.

1 files changed, 125 insertions, 0 deletions

diff --git a/tests/site_scons/site_tools/nanopb.py b/tests/site_scons/site_tools/nanopb.py
new file mode 100644
index 00000000..0ed70464
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+++ b/tests/site_scons/site_tools/nanopb.py
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+'''
+Scons Builder for nanopb .proto definitions.
+
+This tool will locate the nanopb generator and use it to generate .pb.c and
+.pb.h files from the .proto files.
+
+Basic example
+-------------
+# Build myproto.pb.c and myproto.pb.h from myproto.proto
+myproto = env.NanopbProto("myproto")
+
+# Link nanopb core to the program
+env.Append(CPPPATH = "$NANOB")
+myprog = env.Program(["myprog.c", myproto, "$NANOPB/pb_encode.c", "$NANOPB/pb_decode.c"])
+
+Configuration options
+---------------------
+Normally, this script is used in the test environment of nanopb and it locates
+the nanopb generator by a relative path. If this script is used in another
+application, the path to nanopb root directory has to be defined:
+
+env.SetDefault(NANOPB = "path/to/nanopb")
+
+Additionally, the path to protoc and the options to give to protoc can be
+defined manually:
+
+env.SetDefault(PROTOC = "path/to/protoc")
+env.SetDefault(PROTOCFLAGS = "--plugin=protoc-gen-nanopb=path/to/protoc-gen-nanopb")
+'''
+
+import SCons.Action
+import SCons.Builder
+import SCons.Util
+import os.path
+
+class NanopbWarning(SCons.Warnings.Warning):
+    pass
+SCons.Warnings.enableWarningClass(NanopbWarning)
+
+def _detect_nanopb(env):
+    '''Find the path to nanopb root directory.'''
+    if env.has_key('NANOPB'):
+        # Use nanopb dir given by user
+        return env['NANOPB']
+    
+    p = os.path.abspath(os.path.join(os.path.dirname(__file__), '..', '..', '..'))
+    if os.path.isdir(p) and os.path.isfile(os.path.join(p, 'pb.h')):
+        # Assume we are running under tests/site_scons/site_tools
+        return p
+    
+    raise SCons.Errors.StopError(NanopbWarning,
+        "Could not find the nanopb root directory")
+
+def _detect_protoc(env):
+    '''Find the path to the protoc compiler.'''
+    if env.has_key('PROTOC'):
+        # Use protoc defined by user
+        return env['PROTOC']
+    
+    p = _detect_nanopb(env)
+    p1 = os.path.join(p, 'generator-bin', 'protoc')
+    if os.path.exists(p1):
+        # Use protoc bundled with binary package
+        return p1
+    
+    p = env.WhereIs('protoc')
+    if p:
+        # Use protoc from path
+        return p
+    
+    raise SCons.Errors.StopError(NanopbWarning,
+        "Could not find the protoc compiler")
+
+def _detect_protocflags(env):
+    '''Find the options to use for protoc.'''
+    if env.has_key('PROTOCFLAGS'):
+        return env['PROTOCFLAGS']
+    
+    p = _detect_protoc(env)
+    n = _detect_nanopb(env)
+    if p == os.path.join(n, 'generator-bin', 'protoc'):
+        # Using the bundled protoc, no options needed
+        return ''
+    
+    e = env['ESCAPE']
+    if env['PLATFORM'] == 'win32':
+        return e('--plugin=protoc-gen-nanopb=' + os.path.join(n, 'generator', 'protoc-gen-nanopb.bat'))
+    else:
+        return e('--plugin=protoc-gen-nanopb=' + os.path.join(n, 'generator', 'protoc-gen-nanopb'))
+
+def _nanopb_proto_actions(source, target, env, for_signature):
+    esc = env['ESCAPE']
+    dirs = ' '.join(['-I' + esc(env.GetBuildPath(d)) for d in env['PROTOCPATH']])
+    return '$PROTOC $PROTOCFLAGS %s --nanopb_out=. %s' % (dirs, esc(str(source[0])))
+
+def _nanopb_proto_emitter(target, source, env):
+    basename = os.path.splitext(str(source[0]))[0]
+    target.append(basename + '.pb.h')
+    
+    if os.path.exists(basename + '.options'):
+        source.append(basename + '.options')
+    
+    return target, source
+
+_nanopb_proto_builder = SCons.Builder.Builder(
+    generator = _nanopb_proto_actions,
+    suffix = '.pb.c',
+    src_suffix = '.proto',
+    emitter = _nanopb_proto_emitter)
+       
+def generate(env):
+    '''Add Builder for nanopb protos.'''
+    
+    env['NANOPB'] = _detect_nanopb(env)
+    env['PROTOC'] = _detect_protoc(env)
+    env['PROTOCFLAGS'] = _detect_protocflags(env)
+    
+    env.SetDefault(PROTOCPATH = ['.', os.path.join(env['NANOPB'], 'generator', 'proto')])
+    
+    env.SetDefault(NANOPB_PROTO_CMD = '$PROTOC $PROTOC_OPTS --nanopb_out=. $SOURCE')
+    env['BUILDERS']['NanopbProto'] = _nanopb_proto_builder
+    
+def exists(env):
+    return _detect_protoc(env) and _detect_protoc_opts(env)
+