Merge pull request #6902 from xclaesse/auto-fallback

Implicit dependency fallback when a subproject wrap or dir exists

1 files changed, 110 insertions, 25 deletions

diff --git a/mesonbuild/wrap/wrap.py b/mesonbuild/wrap/wrap.py
index 689fb4f..e0c7a04 100644
--- a/mesonbuild/wrap/wrap.py
+++ b/mesonbuild/wrap/wrap.py
@@ -103,14 +103,31 @@ class WrapNotFoundException(WrapException):
 
 class PackageDefinition:
     def __init__(self, fname: str):
-        self.filename = fname
+        self.type = None
+        self.values = {} # type: T.Dict[str, str]
+        self.provided_deps = {} # type: T.Dict[str, T.Optional[str]]
+        self.provided_programs = [] # type: T.List[str]
         self.basename = os.path.basename(fname)
-        self.name = self.basename[:-5]
+        self.name = self.basename
+        if self.name.endswith('.wrap'):
+            self.name = self.name[:-5]
+        self.provided_deps[self.name] = None
+        if fname.endswith('.wrap'):
+            self.parse_wrap(fname)
+        self.directory = self.values.get('directory', self.name)
+        if os.path.dirname(self.directory):
+            raise WrapException('Directory key must be a name and not a path')
+
+    def parse_wrap(self, fname: str):
         try:
             self.config = configparser.ConfigParser(interpolation=None)
             self.config.read(fname)
         except configparser.Error:
             raise WrapException('Failed to parse {}'.format(self.basename))
+        self.parse_wrap_section()
+        self.parse_provide_section()
+
+    def parse_wrap_section(self):
         if len(self.config.sections()) < 1:
             raise WrapException('Missing sections in {}'.format(self.basename))
         self.wrap_section = self.config.sections()[0]
@@ -120,6 +137,27 @@ class PackageDefinition:
         self.type = self.wrap_section[5:]
         self.values = dict(self.config[self.wrap_section])
 
+    def parse_provide_section(self):
+        if self.config.has_section('provide'):
+            for k, v in self.config['provide'].items():
+                if k == 'dependency_names':
+                    # A comma separated list of dependency names that does not
+                    # need a variable name
+                    names = {n.strip(): None for n in v.split(',')}
+                    self.provided_deps.update(names)
+                    continue
+                if k == 'program_names':
+                    # A comma separated list of program names
+                    names = [n.strip() for n in v.split(',')]
+                    self.provided_programs += names
+                    continue
+                if not v:
+                    m = ('Empty dependency variable name for {!r} in {}. '
+                         'If the subproject uses meson.override_dependency() '
+                         'it can be added in the "dependency_names" special key.')
+                    raise WrapException(m.format(k, self.basename))
+                self.provided_deps[k] = v
+
     def get(self, key: str) -> str:
         try:
             return self.values[key]
@@ -127,35 +165,87 @@ class PackageDefinition:
             m = 'Missing key {!r} in {}'
             raise WrapException(m.format(key, self.basename))
 
-def load_wrap(subdir_root: str, packagename: str) -> PackageDefinition:
+def get_directory(subdir_root: str, packagename: str) -> str:
     fname = os.path.join(subdir_root, packagename + '.wrap')
     if os.path.isfile(fname):
-        return PackageDefinition(fname)
-    return None
-
-def get_directory(subdir_root: str, packagename: str):
-    directory = packagename
-    # We always have to load the wrap file, if it exists, because it could
-    # override the default directory name.
-    wrap = load_wrap(subdir_root, packagename)
-    if wrap and 'directory' in wrap.values:
-        directory = wrap.get('directory')
-        if os.path.dirname(directory):
-            raise WrapException('Directory key must be a name and not a path')
-    return wrap, directory
+        wrap = PackageDefinition(fname)
+        return wrap.directory
+    return packagename
 
 class Resolver:
-    def __init__(self, subdir_root: str, wrap_mode=WrapMode.default, current_subproject: str = ''):
+    def __init__(self, subdir_root: str, wrap_mode=WrapMode.default):
         self.wrap_mode = wrap_mode
         self.subdir_root = subdir_root
-        self.current_subproject = current_subproject
         self.cachedir = os.path.join(self.subdir_root, 'packagecache')
         self.filesdir = os.path.join(self.subdir_root, 'packagefiles')
+        self.wraps = {} # type: T.Dict[str, PackageDefinition]
+        self.provided_deps = {} # type: T.Dict[str, PackageDefinition]
+        self.provided_programs = {} # type: T.Dict[str, PackageDefinition]
+        self.load_wraps()
 
-    def resolve(self, packagename: str, method: str) -> str:
+    def load_wraps(self):
+        if not os.path.isdir(self.subdir_root):
+            return
+        root, dirs, files = next(os.walk(self.subdir_root))
+        for i in files:
+            if not i.endswith('.wrap'):
+                continue
+            fname = os.path.join(self.subdir_root, i)
+            wrap = PackageDefinition(fname)
+            self.wraps[wrap.name] = wrap
+            if wrap.directory in dirs:
+                dirs.remove(wrap.directory)
+        # Add dummy package definition for directories not associated with a wrap file.
+        for i in dirs:
+            if i in ['packagecache', 'packagefiles']:
+                continue
+            fname = os.path.join(self.subdir_root, i)
+            wrap = PackageDefinition(fname)
+            self.wraps[wrap.name] = wrap
+
+        for wrap in self.wraps.values():
+            for k in wrap.provided_deps.keys():
+                if k in self.provided_deps:
+                    prev_wrap = self.provided_deps[k]
+                    m = 'Multiple wrap files provide {!r} dependency: {} and {}'
+                    raise WrapException(m.format(k, wrap.basename, prev_wrap.basename))
+                self.provided_deps[k] = wrap
+            for k in wrap.provided_programs:
+                if k in self.provided_programs:
+                    prev_wrap = self.provided_programs[k]
+                    m = 'Multiple wrap files provide {!r} program: {} and {}'
+                    raise WrapException(m.format(k, wrap.basename, prev_wrap.basename))
+                self.provided_programs[k] = wrap
+
+    def find_dep_provider(self, packagename: str):
+        # Return value is in the same format as fallback kwarg:
+        # ['subproject_name', 'variable_name'], or 'subproject_name'.
+        wrap = self.provided_deps.get(packagename)
+        if wrap:
+            dep_var = wrap.provided_deps.get(packagename)
+            if dep_var:
+                return [wrap.name, dep_var]
+            return wrap.name
+        return None
+
+    def find_program_provider(self, names: T.List[str]):
+        for name in names:
+            wrap = self.provided_programs.get(name)
+            if wrap:
+                return wrap.name
+        return None
+
+    def resolve(self, packagename: str, method: str, current_subproject: str = '') -> str:
+        self.current_subproject = current_subproject
         self.packagename = packagename
-        self.wrap, self.directory = get_directory(self.subdir_root, self.packagename)
+        self.directory = packagename
+        self.wrap = self.wraps.get(packagename)
+        if not self.wrap:
+            m = 'Subproject directory not found and {}.wrap file not found'
+            raise WrapNotFoundException(m.format(self.packagename))
+        self.directory = self.wrap.directory
         self.dirname = os.path.join(self.subdir_root, self.directory)
+
         meson_file = os.path.join(self.dirname, 'meson.build')
         cmake_file = os.path.join(self.dirname, 'CMakeLists.txt')
 
@@ -175,11 +265,6 @@ class Resolver:
             if not os.path.isdir(self.dirname):
                 raise WrapException('Path already exists but is not a directory')
         else:
-            # A wrap file is required to download
-            if not self.wrap:
-                m = 'Subproject directory not found and {}.wrap file not found'
-                raise WrapNotFoundException(m.format(self.packagename))
-
             if self.wrap.type == 'file':
                 self.get_file()
             else: