vala: Implement valac.find_library

Move CCompiler.compile to Compiler.compile so that ValaCompiler can use
it. Also rewrite ValaCompiler.sanity_check to use it since it does
a simple compile check.

At the same time, it enhances ExternalLibrary to support arguments for
languages other than C-like.

Includes a test for this that links against zlib through Vala.

Closes #983

mesonbuild/backend/ninjabackend.py

@@ -1045,6 +1045,8 @@ int dummy;
                    and d.version_requirement.startswith(('>=', '==')):
                     args += ['--target-glib', d.version_requirement[2:]]
                 args += ['--pkg', d.name]
+            elif isinstance(d, dependencies.ExternalLibrary):
+                args += d.get_lang_args('vala')
         extra_args = []
 
         for a in target.extra_args.get('vala', []):

mesonbuild/compilers.py

@@ -430,6 +430,51 @@ class Compiler():
                     extra_flags += environment.cross_info.config['properties'].get(lang_link_args_key, [])
         return extra_flags
 
+    @contextlib.contextmanager
+    def compile(self, code, extra_args=None):
+        if extra_args is None:
+            extra_args = []
+
+        try:
+            with tempfile.TemporaryDirectory() as tmpdirname:
+                if isinstance(code, str):
+                    srcname = os.path.join(tmpdirname,
+                                           'testfile.' + self.default_suffix)
+                    with open(srcname, 'w') as ofile:
+                        ofile.write(code)
+                elif isinstance(code, mesonlib.File):
+                    srcname = code.fname
+
+                # Extension only matters if running results; '.exe' is
+                # guaranteed to be executable on every platform.
+                output = os.path.join(tmpdirname, 'output.exe')
+
+                commands = self.get_exelist()
+                commands.append(srcname)
+                commands += extra_args
+                commands += self.get_output_args(output)
+                mlog.debug('Running compile:')
+                mlog.debug('Working directory: ', tmpdirname)
+                mlog.debug('Command line: ', ' '.join(commands), '\n')
+                mlog.debug('Code:\n', code)
+                p = subprocess.Popen(commands, cwd=tmpdirname,
+                                     stdout=subprocess.PIPE,
+                                     stderr=subprocess.PIPE)
+                (stde, stdo) = p.communicate()
+                stde = stde.decode()
+                stdo = stdo.decode()
+                mlog.debug('Compiler stdout:\n', stdo)
+                mlog.debug('Compiler stderr:\n', stde)
+
+                p.input_name = srcname
+                p.output_name = output
+                yield p
+        except (PermissionError, OSError):
+            # On Windows antivirus programs and the like hold on to files so
+            # they can't be deleted. There's not much to do in this case. Also,
+            # catch OSError because the directory is then no longer empty.
+            pass
+
     def get_colorout_args(self, colortype):
         return []
 
@@ -659,51 +704,6 @@ int main () {{
         args = extra_args + self.get_compiler_check_args()
         return self.compiles(templ.format(hname, symbol, prefix), env, args, dependencies)
 
-    @contextlib.contextmanager
-    def compile(self, code, extra_args=None):
-        if extra_args is None:
-            extra_args = []
-
-        try:
-            with tempfile.TemporaryDirectory() as tmpdirname:
-                if isinstance(code, str):
-                    srcname = os.path.join(tmpdirname,
-                                           'testfile.' + self.default_suffix)
-                    with open(srcname, 'w') as ofile:
-                        ofile.write(code)
-                elif isinstance(code, mesonlib.File):
-                    srcname = code.fname
-
-                # Extension only matters if running results; '.exe' is
-                # guaranteed to be executable on every platform.
-                output = os.path.join(tmpdirname, 'output.exe')
-
-                commands = self.get_exelist()
-                commands.append(srcname)
-                commands += extra_args
-                commands += self.get_output_args(output)
-                mlog.debug('Running compile:')
-                mlog.debug('Working directory: ', tmpdirname)
-                mlog.debug('Command line: ', ' '.join(commands), '\n')
-                mlog.debug('Code:\n', code)
-                p = subprocess.Popen(commands, cwd=tmpdirname,
-                                     stdout=subprocess.PIPE,
-                                     stderr=subprocess.PIPE)
-                (stde, stdo) = p.communicate()
-                stde = stde.decode()
-                stdo = stdo.decode()
-                mlog.debug('Compiler stdout:\n', stdo)
-                mlog.debug('Compiler stderr:\n', stde)
-
-                p.input_name = srcname
-                p.output_name = output
-                yield p
-        except (PermissionError, OSError):
-            # On Windows antivirus programs and the like hold on to files so
-            # they can't be deleted. There's not much to do in this case. Also,
-            # catch OSError because the directory is then no longer empty.
-            pass
-
     def compiles(self, code, env, extra_args=None, dependencies=None):
         if extra_args is None:
             extra_args = []
@@ -1330,27 +1330,48 @@ class ValaCompiler(Compiler):
     def needs_static_linker(self):
         return False # Because compiles into C.
 
+    def get_output_args(self, target):
+        return ['-o', target]
+
     def get_werror_args(self):
         return ['--fatal-warnings']
 
     def sanity_check(self, work_dir, environment):
-        src = 'valatest.vala'
-        source_name = os.path.join(work_dir, src)
-        with open(source_name, 'w') as ofile:
-            ofile.write('''class SanityCheck : Object {
-}
-''')
-        extra_flags = self.get_cross_extra_flags(environment, compile=True, link=False)
-        pc = subprocess.Popen(self.exelist + extra_flags + ['-C', '-c', src], cwd=work_dir)
-        pc.wait()
-        if pc.returncode != 0:
-            raise EnvironmentException('Vala compiler %s can not compile programs.' % self.name_string())
+        code = 'class MesonSanityCheck : Object { }'
+        args = self.get_cross_extra_flags(environment, compile=True, link=False)
+        args += ['-C']
+        with self.compile(code, args) as p:
+            if p.returncode != 0:
+                msg = 'Vala compiler {!r} can not compile programs' \
+                      ''.format(self.name_string())
+                raise EnvironmentException(msg)
 
     def get_buildtype_args(self, buildtype):
         if buildtype == 'debug' or buildtype == 'debugoptimized' or buildtype == 'minsize':
             return ['--debug']
         return []
 
+    def find_library(self, libname, env, extra_dirs):
+        if extra_dirs and isinstance(extra_dirs, str):
+            extra_dirs = [extra_dirs]
+        # Valac always looks in the default vapi dir, so only search there if
+        # no extra dirs are specified.
+        if len(extra_dirs) == 0:
+            code = 'class MesonFindLibrary : Object { }'
+            vapi_args = ['--pkg', libname]
+            args = self.get_cross_extra_flags(env, compile=True, link=False)
+            args += ['-C'] + vapi_args
+            with self.compile(code, args) as p:
+                if p.returncode == 0:
+                    return vapi_args
+        # Not found? Try to find the vapi file itself.
+        for d in extra_dirs:
+            vapi = os.path.join(d, libname + '.vapi')
+            if os.path.isfile(vapi):
+                return vapi
+        mlog.debug('Searched {!r} and {!r} wasn\'t found'.format(extra_dirs, libname))
+        return None
+
 class RustCompiler(Compiler):
     def __init__(self, exelist, version):
         self.language = 'rust'

mesonbuild/dependencies.py

@@ -455,29 +455,37 @@ class ExternalProgram():
         return self.name
 
 class ExternalLibrary(Dependency):
-    def __init__(self, name, link_args=None, silent=False):
+    # TODO: Add `lang` to the parent Dependency object so that dependencies can
+    # be expressed for languages other than C-like
+    def __init__(self, name, link_args=None, language=None, silent=False):
         super().__init__('external')
         self.name = name
-        # Rename fullpath to link_args once standalone find_library() gets removed.
-        if link_args is not None:
-            if isinstance(link_args, list):
-                self.link_args = link_args
+        self.is_found = False
+        self.link_args = []
+        self.lang_args = []
+        if link_args:
+            self.is_found = True
+            if not isinstance(link_args, list):
+                link_args = [link_args]
+            if language:
+                self.lang_args = {language: link_args}
             else:
-                self.link_args = [link_args]
-        else:
-            self.link_args = link_args
+                self.link_args = link_args
         if not silent:
-            if self.found():
+            if self.is_found:
                 mlog.log('Library', mlog.bold(name), 'found:', mlog.green('YES'))
             else:
                 mlog.log('Library', mlog.bold(name), 'found:', mlog.red('NO'))
 
     def found(self):
-        return self.link_args is not None
+        return self.is_found
 
     def get_link_args(self):
-        if self.found():
-            return self.link_args
+        return self.link_args
+
+    def get_lang_args(self, lang):
+        if lang in self.lang_args:
+            return self.lang_args[lang]
         return []
 
 class BoostDependency(Dependency):

mesonbuild/interpreter.py

@@ -944,9 +944,17 @@ class CompilerHolder(InterpreterObject):
             if not os.path.isabs(i):
                 raise InvalidCode('Search directory %s is not an absolute path.' % i)
         linkargs = self.compiler.find_library(libname, self.environment, search_dirs)
-        if required and linkargs is None:
-            raise InterpreterException('Library {} not found'.format(libname))
-        lib = dependencies.ExternalLibrary(libname, linkargs)
+        if required and not linkargs:
+            l = self.compiler.language.capitalize()
+            raise InterpreterException('{} library {!r} not found'.format(l, libname))
+        # If this is set to None, the library and link arguments are for
+        # a C-like compiler. Otherwise, it's for some other language that has
+        # a find_library implementation. We do this because it's easier than
+        # maintaining a list of languages that can consume C libraries.
+        lang = None
+        if self.compiler.language == 'vala':
+            lang = 'vala'
+        lib = dependencies.ExternalLibrary(libname, linkargs, language=lang)
         return ExternalLibraryHolder(lib)
 
     def has_argument_method(self, args, kwargs):

test cases/vala/13 find library/meson.build

@@ -0,0 +1,9 @@
+project('find vala library', 'vala', 'c')
+
+valac = meson.get_compiler('vala')
+
+gobject = dependency('gobject-2.0')
+zlib = valac.find_library('zlib')
+
+e = executable('zlibtest', 'test.vala', dependencies : [gobject, zlib])
+test('testzlib', e)

test cases/vala/13 find library/test.vala

@@ -0,0 +1,6 @@
+using ZLib;
+
+public static int main(string[] args) {
+    stdout.printf("ZLIB_VERSION is: %s\n", ZLib.VERSION.STRING);
+    return 0;
+}

test cases/vala/4 config/meson-something-else.vapi

@@ -0,0 +1 @@
+public const string SOMETHING_ELSE;

test cases/vala/4 config/meson.build

@@ -1,11 +1,15 @@
 project('valatest', 'vala', 'c')
 
-valadeps = [dependency('glib-2.0'), dependency('gobject-2.0')]
+valac = meson.get_compiler('vala')
+# Try to find our library
+valadeps = [valac.find_library('meson-something-else', dirs : meson.current_source_dir())]
+valadeps += [dependency('glib-2.0'), dependency('gobject-2.0')]
 
 e = executable(
 'valaprog',
 sources : ['config.vapi', 'prog.vala'],
 dependencies : valadeps,
-c_args : '-DDATA_DIRECTORY="@0@"'.format(meson.current_source_dir())
+c_args : ['-DDATA_DIRECTORY="@0@"'.format(meson.current_source_dir()),
+          '-DSOMETHING_ELSE="Out of this world!"']
 )
 test('valatest', e)

test cases/vala/4 config/prog.vala

@@ -2,6 +2,7 @@ class MainProg : GLib.Object {
 
     public static int main(string[] args) {
         stdout.printf("DATA_DIRECTORY is: %s.\n", DATA_DIRECTORY);
+        stdout.printf("SOMETHING_ELSE is: %s.\n", SOMETHING_ELSE);
         return 0;
     }
 }