dependencies: Add a new class ExternalDependency

This class now consolidates a lot of the logic that each external
dependency was duplicating in its class definition.

All external dependencies now set:

* self.version
* self.compile_args and self.link_args
* self.is_found (if found)
* self.sources
* etc

And the abstract ExternalDependency class defines the methods that
will fetch those properties. Some classes still override that for
various reasons, but those should also be migrated to properties as
far as possible.

Next step is to consolidate and standardize the way in which we call
'configuration binaries' such as sdl2-config, llvm-config, pkg-config,
etc. Currently each class has to duplicate code involved with that
even though the format is very similar.

Currently only pkg-config supports multiple version requirements, and
some classes don't even properly check the version requirement. That
will also become easier now.

1 files changed, 24 insertions, 49 deletions

diff --git a/mesonbuild/dependencies/misc.py b/mesonbuild/dependencies/misc.py
index 6a76ba6..1356ec8 100644
--- a/mesonbuild/dependencies/misc.py
+++ b/mesonbuild/dependencies/misc.py
@@ -23,25 +23,19 @@ from .. import mlog
 from .. import mesonlib
 from ..environment import detect_cpu_family
 
-from .base import Dependency, DependencyException, DependencyMethods, ExtraFrameworkDependency, PkgConfigDependency
+from .base import DependencyException, DependencyMethods
+from .base import ExternalDependency, ExtraFrameworkDependency, PkgConfigDependency
 
 
-class BoostDependency(Dependency):
+class BoostDependency(ExternalDependency):
     # Some boost libraries have different names for
     # their sources and libraries. This dict maps
     # between the two.
     name2lib = {'test': 'unit_test_framework'}
 
     def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'boost', kwargs)
-        self.name = 'boost'
-        self.environment = environment
+        super().__init__('boost', environment, 'cpp', kwargs)
         self.libdir = ''
-        self.static = kwargs.get('static', False)
-        if 'native' in kwargs and environment.is_cross_build():
-            self.want_cross = not kwargs['native']
-        else:
-            self.want_cross = environment.is_cross_build()
         try:
             self.boost_root = os.environ['BOOST_ROOT']
             if not os.path.isabs(self.boost_root):
@@ -72,7 +66,7 @@ class BoostDependency(Dependency):
         self.detect_version()
         self.requested_modules = self.get_requested(kwargs)
         module_str = ', '.join(self.requested_modules)
-        if self.version is not None:
+        if self.is_found:
             self.detect_src_modules()
             self.detect_lib_modules()
             self.validate_requested()
@@ -83,9 +77,6 @@ class BoostDependency(Dependency):
             mlog.log('Dependency Boost (%s) found:' % module_str, mlog.green('YES'), info)
         else:
             mlog.log("Dependency Boost (%s) found:" % module_str, mlog.red('NO'))
-        if 'cpp' not in self.environment.coredata.compilers:
-            raise DependencyException('Tried to use Boost but a C++ compiler is not defined.')
-        self.cpp_compiler = self.environment.coredata.compilers['cpp']
 
     def detect_win_root(self):
         globtext = 'c:\\local\\boost_*'
@@ -130,7 +121,7 @@ class BoostDependency(Dependency):
         # names in order to handle cases like cross-compiling where we
         # might have a different sysroot.
         if not include_dir.endswith(('/usr/include', '/usr/local/include')):
-            args.append("".join(self.cpp_compiler.get_include_args(include_dir, True)))
+            args.append("".join(self.compiler.get_include_args(include_dir, True)))
         return args
 
     def get_requested(self, kwargs):
@@ -147,17 +138,10 @@ class BoostDependency(Dependency):
             if m not in self.src_modules:
                 raise DependencyException('Requested Boost module "%s" not found.' % m)
 
-    def found(self):
-        return self.version is not None
-
-    def get_version(self):
-        return self.version
-
     def detect_version(self):
         try:
             ifile = open(os.path.join(self.boost_inc_subdir, 'version.hpp'))
         except FileNotFoundError:
-            self.version = None
             return
         with ifile:
             for line in ifile:
@@ -165,8 +149,8 @@ class BoostDependency(Dependency):
                     ver = line.split()[-1]
                     ver = ver[1:-1]
                     self.version = ver.replace('_', '.')
+                    self.is_found = True
                     return
-        self.version = None
 
     def detect_src_modules(self):
         for entry in os.listdir(self.boost_inc_subdir):
@@ -180,7 +164,7 @@ class BoostDependency(Dependency):
         return self.detect_lib_modules_nix()
 
     def detect_lib_modules_win(self):
-        arch = detect_cpu_family(self.environment.coredata.compilers)
+        arch = detect_cpu_family(self.env.coredata.compilers)
         # Guess the libdir
         if arch == 'x86':
             gl = 'lib32*'
@@ -254,10 +238,10 @@ class BoostDependency(Dependency):
             module = BoostDependency.name2lib.get(module, module)
             libname = 'boost_' + module
             # The compiler's library detector is the most reliable so use that first.
-            default_detect = self.cpp_compiler.find_library(libname, self.environment, [])
+            default_detect = self.compiler.find_library(libname, self.env, [])
             if default_detect is not None:
                 if module == 'unit_testing_framework':
-                    emon_args = self.cpp_compiler.find_library('boost_test_exec_monitor')
+                    emon_args = self.compiler.find_library('boost_test_exec_monitor')
                 else:
                     emon_args = None
                 args += default_detect
@@ -286,9 +270,9 @@ class BoostDependency(Dependency):
         return 'thread' in self.requested_modules
 
 
-class ThreadDependency(Dependency):
+class ThreadDependency(ExternalDependency):
     def __init__(self, environment, kwargs):
-        super().__init__('threads', {})
+        super().__init__('threads', environment, None, {})
         self.name = 'threads'
         self.is_found = True
         mlog.log('Dependency', mlog.bold(self.name), 'found:', mlog.green('YES'))
@@ -300,19 +284,18 @@ class ThreadDependency(Dependency):
         return 'unknown'
 
 
-class Python3Dependency(Dependency):
+class Python3Dependency(ExternalDependency):
     def __init__(self, environment, kwargs):
-        super().__init__('python3', kwargs)
+        super().__init__('python3', environment, None, kwargs)
         self.name = 'python3'
-        self.is_found = False
         # We can only be sure that it is Python 3 at this point
         self.version = '3'
         if DependencyMethods.PKGCONFIG in self.methods:
             try:
                 pkgdep = PkgConfigDependency('python3', environment, kwargs)
                 if pkgdep.found():
-                    self.cargs = pkgdep.cargs
-                    self.libs = pkgdep.libs
+                    self.compile_args = pkgdep.get_compile_args()
+                    self.link_args = pkgdep.get_link_args()
                     self.version = pkgdep.get_version()
                     self.is_found = True
                     return
@@ -324,10 +307,11 @@ class Python3Dependency(Dependency):
             elif mesonlib.is_osx() and DependencyMethods.EXTRAFRAMEWORK in self.methods:
                 # In OSX the Python 3 framework does not have a version
                 # number in its name.
-                fw = ExtraFrameworkDependency('python', False, None, kwargs)
+                fw = ExtraFrameworkDependency('python', False, None, self.env,
+                                              self.language, kwargs)
                 if fw.found():
-                    self.cargs = fw.get_compile_args()
-                    self.libs = fw.get_link_args()
+                    self.compile_args = fw.get_compile_args()
+                    self.link_args = fw.get_link_args()
                     self.is_found = True
         if self.is_found:
             mlog.log('Dependency', mlog.bold(self.name), 'found:', mlog.green('YES'))
@@ -359,23 +343,17 @@ class Python3Dependency(Dependency):
             return
         inc = sysconfig.get_path('include')
         platinc = sysconfig.get_path('platinclude')
-        self.cargs = ['-I' + inc]
+        self.compile_args = ['-I' + inc]
         if inc != platinc:
-            self.cargs.append('-I' + platinc)
+            self.compile_args.append('-I' + platinc)
         # Nothing exposes this directly that I coulf find
         basedir = sysconfig.get_config_var('base')
         vernum = sysconfig.get_config_var('py_version_nodot')
-        self.libs = ['-L{}/libs'.format(basedir),
-                     '-lpython{}'.format(vernum)]
+        self.link_args = ['-L{}/libs'.format(basedir),
+                          '-lpython{}'.format(vernum)]
         self.version = sysconfig.get_config_var('py_version_short')
         self.is_found = True
 
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_link_args(self):
-        return self.libs
-
     def get_methods(self):
         if mesonlib.is_windows():
             return [DependencyMethods.PKGCONFIG, DependencyMethods.SYSCONFIG]
@@ -383,6 +361,3 @@ class Python3Dependency(Dependency):
             return [DependencyMethods.PKGCONFIG, DependencyMethods.EXTRAFRAMEWORK]
         else:
             return [DependencyMethods.PKGCONFIG]
-
-    def get_version(self):
-        return self.version