Hoist trying several dependency detection methods up to find_external_dependency()

find_external_dependency() now makes and iterates over a list of callables
which are constructors with bound arguments for the dependency objects we
are going to attempt to make, so we can consolidate reporting on these
attempts and handling failures in that function.

1 files changed, 43 insertions, 57 deletions

diff --git a/mesonbuild/dependencies/misc.py b/mesonbuild/dependencies/misc.py
index 19874fc..6076433 100644
--- a/mesonbuild/dependencies/misc.py
+++ b/mesonbuild/dependencies/misc.py
@@ -14,6 +14,7 @@
 
 # This file contains the detection logic for miscellaneous external dependencies.
 
+import functools
 import os
 import re
 import shlex
@@ -436,26 +437,21 @@ class PcapDependency(ExternalDependency):
     @classmethod
     def _factory(cls, environment, kwargs):
         methods = cls._process_method_kw(kwargs)
+        candidates = []
+
         if DependencyMethods.PKGCONFIG in methods:
-            try:
-                pcdep = PkgConfigDependency('pcap', environment, kwargs)
-                if pcdep.found():
-                    return pcdep
-            except Exception as e:
-                mlog.debug('Pcap not found via pkgconfig. Trying next, error was:', str(e))
+            candidates.append(functools.partial(PkgConfigDependency, 'pcap', environment, kwargs))
+
         if DependencyMethods.CONFIG_TOOL in methods:
-            try:
-                ctdep = ConfigToolDependency.factory(
-                    'pcap', environment, None, kwargs, ['pcap-config'], 'pcap-config')
-                if ctdep.found():
-                    ctdep.compile_args = ctdep.get_config_value(['--cflags'], 'compile_args')
-                    ctdep.link_args = ctdep.get_config_value(['--libs'], 'link_args')
-                    ctdep.version = cls.get_pcap_lib_version(ctdep)
-                    return ctdep
-            except Exception as e:
-                mlog.debug('Pcap not found via pcap-config. Trying next, error was:', str(e))
-
-        return PcapDependency(environment, kwargs)
+            candidates.append(functools.partial(ConfigToolDependency.factory,
+                    'pcap', environment, None, kwargs, ['pcap-config'], 'pcap-config'))
+#                if ctdep.found():
+#                    ctdep.compile_args = ctdep.get_config_value(['--cflags'], 'compile_args')
+#                    ctdep.link_args = ctdep.get_config_value(['--libs'], 'link_args')
+#                    ctdep.version = cls.get_pcap_lib_version(ctdep)
+#                    return ctdep
+
+        return candidates
 
     @staticmethod
     def get_methods():
@@ -474,32 +470,27 @@ class CupsDependency(ExternalDependency):
     @classmethod
     def _factory(cls, environment, kwargs):
         methods = cls._process_method_kw(kwargs)
+        candidates = []
+
         if DependencyMethods.PKGCONFIG in methods:
-            try:
-                pcdep = PkgConfigDependency('cups', environment, kwargs)
-                if pcdep.found():
-                    return pcdep
-            except Exception as e:
-                mlog.debug('cups not found via pkgconfig. Trying next, error was:', str(e))
+            candidates.append(functools.partial(PkgConfigDependency, 'cups', environment, kwargs))
+
         if DependencyMethods.CONFIG_TOOL in methods:
-            try:
-                ctdep = ConfigToolDependency.factory(
-                    'cups', environment, None, kwargs, ['cups-config'], 'cups-config')
-                if ctdep.found():
-                    ctdep.compile_args = ctdep.get_config_value(['--cflags'], 'compile_args')
-                    ctdep.link_args = ctdep.get_config_value(['--ldflags', '--libs'], 'link_args')
-                    return ctdep
-            except Exception as e:
-                mlog.debug('cups not found via cups-config. Trying next, error was:', str(e))
+            candidates.append(functools.partial(ConfigToolDependency.factory,
+                                                'cups', environment, None,
+                                                kwargs, ['cups-config'],
+                                                'cups-config'))
+#                if ctdep.found():
+#                    ctdep.compile_args = ctdep.get_config_value(['--cflags'], 'compile_args')
+#                    ctdep.link_args = ctdep.get_config_value(['--ldflags', '--libs'], 'link_args')
+
         if DependencyMethods.EXTRAFRAMEWORK in methods:
             if mesonlib.is_osx():
-                fwdep = ExtraFrameworkDependency('cups', False, None, environment,
-                                                 kwargs.get('language', None), kwargs)
-                if fwdep.found():
-                    return fwdep
-        mlog.log('Dependency', mlog.bold('cups'), 'found:', mlog.red('NO'))
+                candidates.append(functools.partial(
+                    ExtraFrameworkDependency, 'cups', False, None, environment,
+                    kwargs.get('language', None), kwargs))
 
-        return CupsDependency(environment, kwargs)
+        return candidates
 
     @staticmethod
     def get_methods():
@@ -516,26 +507,21 @@ class LibWmfDependency(ExternalDependency):
     @classmethod
     def _factory(cls, environment, kwargs):
         methods = cls._process_method_kw(kwargs)
+        candidates = []
+
         if DependencyMethods.PKGCONFIG in methods:
-            try:
-                kwargs['required'] = False
-                pcdep = PkgConfigDependency('libwmf', environment, kwargs)
-                if pcdep.found():
-                    return pcdep
-            except Exception as e:
-                mlog.debug('LibWmf not found via pkgconfig. Trying next, error was:', str(e))
+            candidates.append(functools.partial(PkgConfigDependency, 'libwmf', environment, kwargs))
+
         if DependencyMethods.CONFIG_TOOL in methods:
-            try:
-                ctdep = ConfigToolDependency.factory(
-                    'libwmf', environment, None, kwargs, ['libwmf-config'], 'libwmf-config')
-                if ctdep.found():
-                    ctdep.compile_args = ctdep.get_config_value(['--cflags'], 'compile_args')
-                    ctdep.link_args = ctdep.get_config_value(['--libs'], 'link_args')
-                    return ctdep
-            except Exception as e:
-                mlog.debug('cups not found via libwmf-config. Trying next, error was:', str(e))
-
-        return LibWmfDependency(environment, kwargs)
+            candidates.append(functools.partial(ConfigToolDependency.factory,
+                    'libwmf', environment, None, kwargs, ['libwmf-config'], 'libwmf-config'))
+
+#                if ctdep.found():
+#                    ctdep.compile_args = ctdep.get_config_value(['--cflags'], 'compile_args')
+#                    ctdep.link_args = ctdep.get_config_value(['--libs'], 'link_args')
+#                    return ctdep
+
+        return candidates
 
     @staticmethod
     def get_methods():