public IPythonModule ImportModule(string name) { if (string.IsNullOrEmpty(name)) { return(null); } // Handle builtins explicitly if (name == BuiltinModuleName) { if (_builtinModule == null) { _modules[BuiltinModuleName] = _builtinModule = new AstBuiltinsPythonModule(_factory.LanguageVersion); _builtinModule.Imported(this); var bmn = ((AstBuiltinsPythonModule)_builtinModule).GetAnyMember("__builtin_module_names") as AstPythonStringLiteral; _builtinModuleNames = bmn?.Value?.Split(','); } return(_builtinModule); } IPythonModule mod; // Return any existing module if (_modules.TryGetValue(name, out mod) && mod != null) { if (mod is EmptyModule) { Trace.TraceWarning($"Recursively importing {name}"); } return(mod); } // Set up a sentinel so we can detect recursive imports var sentinalValue = new EmptyModule(); if (!_modules.TryAdd(name, sentinalValue)) { return(_modules[name]); } // Do normal searches mod = ImportFromBuiltins(name) ?? ImportFromSearchPaths(name); // Replace our sentinel, or if we raced, get the current // value and abandon the one we just created. if (!_modules.TryUpdate(name, mod, sentinalValue)) { mod = _modules[name]; } return(mod); }
private IPythonModule ImportModuleOrRetry(string name, out bool retry) { retry = false; if (string.IsNullOrEmpty(name)) { return(null); } Debug.Assert(!name.EndsWith("."), $"{name} should not end with '.'"); // Handle builtins explicitly if (name == BuiltinModuleName) { if (_builtinModule == null) { _modules[BuiltinModuleName] = _builtinModule = new AstBuiltinsPythonModule(_factory.LanguageVersion); _builtinModuleNames = null; _builtinModule.Imported(this); var bmn = ((AstBuiltinsPythonModule)_builtinModule).GetAnyMember("__builtin_module_names") as AstPythonStringLiteral; _builtinModuleNames = bmn?.Value?.Split(',') ?? Array.Empty <string>(); } return(_builtinModule); } IPythonModule mod; // Return any existing module if (_modules.TryGetValue(name, out mod) && mod != null) { if (mod is SentinelModule smod) { // If we are importing this module on another thread, allow // time for it to complete. This does not block if we are // importing on the current thread or the module is not // really being imported. var newMod = smod.WaitForImport(5000); if (newMod is SentinelModule) { _log?.Log(TraceLevel.Warning, "RecursiveImport", name); mod = newMod; } else if (newMod == null) { _log?.Log(TraceLevel.Warning, "ImportTimeout", name); } else { mod = newMod; } } return(mod); } // Set up a sentinel so we can detect recursive imports var sentinalValue = new SentinelModule(name, true); if (!_modules.TryAdd(name, sentinalValue)) { // Try to get the new module, in case we raced with a .Clear() if (_modules.TryGetValue(name, out mod) && !(mod is SentinelModule)) { return(mod); } // If we reach here, the race is too complicated to recover // from. Signal the caller to try importing again. _log?.Log(TraceLevel.Warning, "RetryImport", name); retry = true; return(null); } // Do normal searches mod = ImportFromBuiltins(name) ?? ImportFromSearchPaths(name); // Replace our sentinel, or if we raced, get the current // value and abandon the one we just created. if (!_modules.TryUpdate(name, mod, sentinalValue)) { // Try to get the new module, in case we raced if (_modules.TryGetValue(name, out mod) && !(mod is SentinelModule)) { return(mod); } // If we reach here, the race is too complicated to recover // from. Signal the caller to try importing again. _log?.Log(TraceLevel.Warning, "RetryImport", name); retry = true; return(null); } sentinalValue.Complete(mod); sentinalValue.Dispose(); return(mod); }