Find and use external libraries.

backends.py

@@ -143,7 +143,8 @@ class Backend():
         if isinstance(target, interpreter.SharedLibrary):
             commands += compiler.get_pic_flags()
         for dep in target.get_external_deps():
-            commands += dep.get_compile_flags()
+            if isinstance(dep, environment.Dependency):
+                commands += dep.get_compile_flags()
         return commands
 
     def build_target_link_arguments(self, deps):
@@ -537,7 +538,10 @@ class NinjaBackend(Backend):
         else:
             raise RuntimeError('Unknown build target type.')
         for dep in target.get_external_deps():
-            commands += dep.get_link_flags()
+            if isinstance(dep, environment.Dependency):
+                commands += dep.get_link_flags()
+            else:
+                commands.append(dep.get_filename())
         dependencies = target.get_dependencies()
         commands += self.build_target_link_arguments(dependencies)
         if self.environment.coredata.coverage:

coredata.py

@@ -40,6 +40,7 @@ class CoreData():
         self.compilers = {}
         self.deps = {}
         self.ext_progs = {}
+        self.ext_libs = {}
 
 def load(filename):
     obj = pickle.load(open(filename, 'rb'))

environment.py

@@ -16,6 +16,7 @@
 
 import subprocess, os.path, platform
 import coredata
+from glob import glob
 
 build_filename = 'meson.build'
 
@@ -416,6 +417,27 @@ class Environment():
     def get_datadir(self):
         return self.coredata.datadir
 
+    def find_library(self, libname):
+        dirs = self.get_library_dirs()
+        suffixes = [self.get_shared_lib_suffix(), self.get_static_lib_suffix()]
+        prefix = self.get_shared_lib_prefix()
+        for d in dirs:
+            for suffix in suffixes:
+                trial = os.path.join(d, prefix + libname + '.' + suffix)
+                if os.path.isfile(trial):
+                    return trial
+
+    def get_library_dirs(self):
+        if is_windows():
+            return ['C:/mingw/lib'] # Fixme
+        if is_osx():
+            return ['/usr/lib'] # Fix me as well.
+        unixdirs = ['/usr/lib', '/lib']
+        plat = subprocess.check_output(['uname', '-m']).decode().strip()
+        unixdirs += glob('/usr/lib/' + plat + '*')
+        unixdirs.append('/usr/local/lib')
+        return unixdirs
+
 class Dependency():
     def __init__(self):
         pass

interpreter.py

@@ -40,11 +40,11 @@ class InterpreterObject():
         raise InvalidCode('Unknown method "%s" in object.' % method_name)
 
 class ExternalProgram(InterpreterObject):
-    
     def __init__(self, name, fullpath=None):
         InterpreterObject.__init__(self)
         self.name = name
         self.fullpath = fullpath
+        #self.methods.update({'found': self.found_method})
 
     def found(self):
         return self.fullpath is not None
@@ -58,6 +58,25 @@ class ExternalProgram(InterpreterObject):
     def get_name(self):
         return self.name
 
+class ExternalLibrary(InterpreterObject):
+    def __init__(self, name, fullpath=None):
+        InterpreterObject.__init__(self)
+        self.name = name
+        self.fullpath = fullpath
+        #self.methods.update({'found': self.found_method})
+
+    def found(self):
+        return self.fullpath is not None
+
+    def found_method(self, args, kwargs):
+        return self.found()
+
+    def get_filename(self):
+        return self.fullpath
+
+    def get_name(self):
+        return self.name
+
 class Generator(InterpreterObject):
 
     def __init__(self, args, kwargs):
@@ -349,7 +368,8 @@ class BuildTarget(InterpreterObject):
 
     def add_external_deps(self, deps):
         for dep in deps:
-            if not isinstance(dep, environment.Dependency):
+            if not isinstance(dep, environment.Dependency) and\
+               not isinstance(dep, ExternalLibrary):
                 raise InvalidArguments('Argument is not an external dependency')
             self.external_deps.append(dep)
 
@@ -496,6 +516,7 @@ class Interpreter():
                       'include_directories' : self.func_include_directories,
                       'add_global_arguments' : self.func_add_global_arguments,
                       'find_program' : self.func_find_program,
+                      'find_library' : self.func_find_library,
                       }
 
     def get_build_def_files(self):
@@ -625,6 +646,22 @@ class Interpreter():
             raise InvalidArguments('Line %d: program "%s" not found.' % (node.lineno(), exename))
         return progobj
 
+    def func_find_library(self, node, args, kwargs):
+        self.validate_arguments(args, 1, [str])
+        required = kwargs.get('required', False)
+        if not isinstance(required, bool):
+            raise InvalidArguments('Line %d: "required" argument must be a boolean.' % node.lineno())
+        libname = args[0]
+        if libname in self.coredata.ext_libs and\
+           self.coredata.ext_libs[libname].found():
+            return self.coredata.ext_progs[libname]
+        result = self.environment.find_library(libname)
+        libobj = ExternalLibrary(libname, result)
+        self.coredata.ext_libs[libname] = libobj
+        if required and not libobj.found():
+            raise InvalidArguments('Line %d: external library "%s" not found.' % (node.lineno(), libname))
+        return libobj
+
     def func_find_dep(self, node, args, kwargs):
         self.validate_arguments(args, 1, [str])
         name = args[0]

test cases/linuxlike/2 external library/meson.build

@@ -0,0 +1,5 @@
+project('external library', 'c')
+
+zlib = find_library('z', required : true)
+e = executable('zprog', 'prog.c', deps : zlib)
+add_test('libtest', e)

test cases/linuxlike/2 external library/prog.c

@@ -0,0 +1,8 @@
+#include<zlib.h>
+
+int main(int argc, char **argv) {
+    void * something = deflate;
+    if(something != 0)
+        return 0;
+    return 1;
+}