dependencies: Use a DependencyFactory for threads

This lets us make a number of uses of threads safer, because we can use
the threads_factory instead of the ThreadDependency

6 files changed, 42 insertions, 43 deletions

diff --git a/mesonbuild/dependencies/__init__.py b/mesonbuild/dependencies/__init__.py
index 2626c24..6b91b38 100644
--- a/mesonbuild/dependencies/__init__.py
+++ b/mesonbuild/dependencies/__init__.py
@@ -24,7 +24,7 @@ from .dev import ValgrindDependency, gmock_factory, gtest_factory, llvm_factory
 from .coarrays import CoarrayDependency
 from .mpi import MPIDependency
 from .scalapack import ScalapackDependency
-from .misc import (BlocksDependency, CursesDependency, OpenMPDependency, ThreadDependency, cups_factory, gpgme_factory, libgcrypt_factory, libwmf_factory, netcdf_factory, pcap_factory, python3_factory, shaderc_factory)
+from .misc import (BlocksDependency, CursesDependency, OpenMPDependency, cups_factory, gpgme_factory, libgcrypt_factory, libwmf_factory, netcdf_factory, pcap_factory, python3_factory, shaderc_factory, threads_factory)
 from .platform import AppleFrameworks
 from .ui import GnuStepDependency, Qt4Dependency, Qt5Dependency, WxDependency, gl_factory, sdl2_factory, vulkan_factory
 
@@ -51,7 +51,7 @@ packages.update({
     'netcdf': netcdf_factory,
     'openmp': OpenMPDependency,
     'python3': python3_factory,
-    'threads': ThreadDependency,
+    'threads': threads_factory,
     'pcap': pcap_factory,
     'cups': cups_factory,
     'libwmf': libwmf_factory,
diff --git a/mesonbuild/dependencies/base.py b/mesonbuild/dependencies/base.py
index b6c6f19..c38786b 100644
--- a/mesonbuild/dependencies/base.py
+++ b/mesonbuild/dependencies/base.py
@@ -195,8 +195,8 @@ class Dependency:
                 return True
         return False
 
-    def _add_sub_dependency(self, dep_type: T.Type['Dependency'], env: Environment,
-                            kwargs: T.Dict[str, T.Any], *,
+    def _add_sub_dependency(self, dep_type: T.Type['Dependency'], name: str,
+                            env: Environment, kwargs: T.Dict[str, T.Any], *,
                             method: DependencyMethods = DependencyMethods.AUTO) -> None:
         """Add an internal dependency of of the given type.
 
@@ -207,7 +207,7 @@ class Dependency:
         """
         kwargs = kwargs.copy()
         kwargs['method'] = method
-        self.ext_deps.append(dep_type(env, kwargs))
+        self.ext_deps.append(dep_type(name, env, kwargs))
 
     def get_variable(self, *, cmake: T.Optional[str] = None, pkgconfig: T.Optional[str] = None,
                      configtool: T.Optional[str] = None, internal: T.Optional[str] = None,
diff --git a/mesonbuild/dependencies/boost.py b/mesonbuild/dependencies/boost.py
index 0f7216f..6054313 100644
--- a/mesonbuild/dependencies/boost.py
+++ b/mesonbuild/dependencies/boost.py
@@ -22,7 +22,7 @@ from .. import mesonlib
 from ..environment import detect_cpu_family
 
 from .base import (DependencyException, ExternalDependency)
-from .misc import ThreadDependency
+from .misc import threads_factory
 
 # On windows 3 directory layouts are supported:
 # * The default layout (versioned) installed:
@@ -105,7 +105,9 @@ class BoostDependency(ExternalDependency):
 
         self.requested_modules = self.get_requested(kwargs)
         if 'thread' in self.requested_modules:
-            self._add_sub_dependency(ThreadDependency, environment, kwargs)
+            if not self._add_sub_dependency2(threads_factory(environment, self.for_machine, {})):
+                self.is_found = False
+                return
 
         self.boost_root = None
         self.boost_roots = []
diff --git a/mesonbuild/dependencies/dev.py b/mesonbuild/dependencies/dev.py
index 649975a..9bd6e4f 100644
--- a/mesonbuild/dependencies/dev.py
+++ b/mesonbuild/dependencies/dev.py
@@ -27,7 +27,7 @@ from .base import (
     DependencyException, DependencyMethods, ExternalDependency, PkgConfigDependency,
     strip_system_libdirs, ConfigToolDependency, CMakeDependency, DependencyFactory,
 )
-from .misc import ThreadDependency
+from .misc import threads_factory
 
 if T.TYPE_CHECKING:
     from .. environment import Environment
@@ -50,8 +50,10 @@ class GTestDependencySystem(ExternalDependency):
         super().__init__(name, environment, kwargs, language='cpp')
         self.main = kwargs.get('main', False)
         self.src_dirs = ['/usr/src/gtest/src', '/usr/src/googletest/googletest/src']
+        if not self._add_sub_dependency2(threads_factory(environment, self.for_machine, {})):
+            self.is_found = False
+            return
         self.detect()
-        self._add_sub_dependency(ThreadDependency, environment, kwargs)
 
     def detect(self):
         gtest_detect = self.clib_compiler.find_library("gtest", self.env, [])
@@ -117,7 +119,9 @@ class GMockDependencySystem(ExternalDependency):
     def __init__(self, name: str, environment, kwargs):
         super().__init__(name, environment, kwargs, language='cpp')
         self.main = kwargs.get('main', False)
-        self._add_sub_dependency(ThreadDependency, environment, kwargs)
+        if not self._add_sub_dependency2(threads_factory(environment, self.for_machine, {})):
+            self.is_found = False
+            return
 
         # If we are getting main() from GMock, we definitely
         # want to avoid linking in main() from GTest
@@ -231,7 +235,9 @@ class LLVMDependencyConfigTool(ConfigToolDependency):
             self._set_old_link_args()
         self.link_args = strip_system_libdirs(environment, self.for_machine, self.link_args)
         self.link_args = self.__fix_bogus_link_args(self.link_args)
-        self._add_sub_dependency(ThreadDependency, environment, kwargs)
+        if not self._add_sub_dependency2(threads_factory(environment, self.for_machine, {})):
+            self.is_found = False
+            return
 
     def __fix_bogus_link_args(self, args):
         """This function attempts to fix bogus link arguments that llvm-config
@@ -394,7 +400,9 @@ class LLVMDependencyCMake(CMakeDependency):
         defs = self.traceparser.get_cmake_var('PACKAGE_DEFINITIONS')
         temp = ['-I' + x for x in inc_dirs] + defs
         self.compile_args += [x for x in temp if x not in self.compile_args]
-        self._add_sub_dependency(ThreadDependency, env, kwargs)
+        if not self._add_sub_dependency2(threads_factory(env, self.for_machine, {})):
+            self.is_found = False
+            return
 
     def _main_cmake_file(self) -> str:
         # Use a custom CMakeLists.txt for LLVM
diff --git a/mesonbuild/dependencies/misc.py b/mesonbuild/dependencies/misc.py
index 6a05ef1..7eba808 100644
--- a/mesonbuild/dependencies/misc.py
+++ b/mesonbuild/dependencies/misc.py
@@ -105,33 +105,17 @@ class OpenMPDependency(ExternalDependency):
 
 
 class ThreadDependency(ExternalDependency):
-    def __init__(self, environment, kwargs):
-        super().__init__('threads', environment, kwargs)
-        self.name = 'threads'
-        self.is_found = False
-        methods = listify(self.methods)
-        if DependencyMethods.AUTO in methods:
-            self.is_found = True
-            # Happens if you are using a language with threads
-            # concept without C, such as plain Cuda.
-            if self.clib_compiler is None:
-                self.compile_args = []
-                self.link_args = []
-            else:
-                self.compile_args = self.clib_compiler.thread_flags(environment)
-                self.link_args = self.clib_compiler.thread_link_flags(environment)
-            return
-
-        if DependencyMethods.CMAKE in methods:
-            # for unit tests and for those who simply want
-            # dependency('threads', method: 'cmake')
-            cmakedep = CMakeDependency('Threads', environment, kwargs)
-            if cmakedep.found():
-                self.compile_args = cmakedep.get_compile_args()
-                self.link_args = cmakedep.get_link_args()
-                self.version = cmakedep.get_version()
-                self.is_found = True
-                return
+    def __init__(self, name: str, environment, kwargs):
+        super().__init__(name, environment, kwargs)
+        self.is_found = True
+        # Happens if you are using a language with threads
+        # concept without C, such as plain Cuda.
+        if self.clib_compiler is None:
+            self.compile_args = []
+            self.link_args = []
+        else:
+            self.compile_args = self.clib_compiler.thread_flags(environment)
+            self.link_args = self.clib_compiler.thread_link_flags(environment)
 
     @staticmethod
     def get_methods():
@@ -508,3 +492,10 @@ python3_factory = DependencyFactory(
     # Python 3 will always be in /Library
     extra_kwargs={'paths': ['/Library/Frameworks']},
 )
+
+threads_factory = DependencyFactory(
+    'threads',
+    [DependencyMethods.SYSTEM, DependencyMethods.CMAKE],
+    cmake_name='Threads',
+    system_class=ThreadDependency,
+)
diff --git a/mesonbuild/modules/pkgconfig.py b/mesonbuild/modules/pkgconfig.py
index dc45a5b..2341bd2 100644
--- a/mesonbuild/modules/pkgconfig.py
+++ b/mesonbuild/modules/pkgconfig.py
@@ -17,6 +17,7 @@ from pathlib import PurePath
 
 from .. import build
 from .. import dependencies
+from ..dependencies.misc import ThreadDependency
 from .. import mesonlib
 from .. import mlog
 from . import ModuleReturnValue
@@ -94,7 +95,7 @@ class DependenciesHelper:
                 self.add_version_reqs(name, version_req)
             elif isinstance(obj, dependencies.Dependency) and not obj.found():
                 pass
-            elif isinstance(obj, dependencies.ThreadDependency):
+            elif isinstance(obj, ThreadDependency):
                 pass
             else:
                 raise mesonlib.MesonException('requires argument not a string, '
@@ -125,9 +126,6 @@ class DependenciesHelper:
                 if obj.found():
                     processed_reqs.append(obj.name)
                     self.add_version_reqs(obj.name, obj.version_reqs)
-            elif isinstance(obj, dependencies.ThreadDependency):
-                processed_libs += obj.get_compiler().thread_link_flags(obj.env)
-                processed_cflags += obj.get_compiler().thread_flags(obj.env)
             elif isinstance(obj, dependencies.InternalDependency):
                 if obj.found():
                     processed_libs += obj.get_link_args()