installd: Replace Dex2oatFileWrapper with UniqueFile
UniqueFile is based on the original Dex2oatFileWrapper, but support
extra features. The class now maintains the file path as a member
variable. This the client to access both fd and file path when they see
fit. As a result, the client no longer provides the cleanup function
with a closure capture, since the class can provide the file path.
Additionally, reduce code duplication in constructors.
Bug: 161470356
Test: atest run_dex2oat_test
Test: atest installd_dexopt_test
Change-Id: I1b66bc58b1885933d1601fdc2f4218c4a262d9f3
diff --git a/cmds/installd/unique_file.h b/cmds/installd/unique_file.h
new file mode 100644
index 0000000..e85e23b
--- /dev/null
+++ b/cmds/installd/unique_file.h
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_INSTALLD_UNIQUE_FILE_H
+#define ANDROID_INSTALLD_UNIQUE_FILE_H
+
+#include <functional>
+#include <string>
+
+namespace android {
+namespace installd {
+
+// A file management helper that serves two purposes:
+//
+// 1. Closes the file description on destruction, similar unique_fd.
+// 2. Runs a cleanup function on after close, if not cancelled.
+//
+// The class does not assume the relationship between the given fd and file path.
+//
+// Example:
+//
+// UniqueFile file(open(...),
+// filepath,
+// [](const std::string& path) {
+// unlink(path.c_str());
+// });
+// if (file.fd() == -1) {
+// // Error opening...
+// }
+//
+// ...
+// if (error) {
+// // At this point, when the UniqueFile is destructed, the cleanup function will run
+// // (e.g. to delete the file) after the fd is closed.
+// return -1;
+// }
+//
+// (Success case)
+// file.DisableCleanup();
+// // At this point, when the UniqueFile is destructed, the cleanup function will not run
+// // (e.g. leaving the file around) after the fd is closed.
+//
+class UniqueFile {
+ private:
+ using CleanUpFunction = std::function<void (const std::string&)>;
+
+ public:
+ UniqueFile();
+ UniqueFile(int value, std::string path);
+ UniqueFile(int value, std::string path, CleanUpFunction cleanup);
+ UniqueFile(UniqueFile&& other);
+ ~UniqueFile();
+
+ UniqueFile& operator=(UniqueFile&& other);
+
+ int fd() const {
+ return value_;
+ }
+
+ const std::string& path() const {
+ return path_;
+ }
+
+ void DisableAutoClose() {
+ auto_close_ = false;
+ }
+
+ void DisableCleanup() {
+ do_cleanup_ = false;
+ }
+
+ void reset();
+ void reset(int new_value, std::string path, CleanUpFunction new_cleanup = nullptr);
+
+ private:
+ void release();
+
+ int value_;
+ std::string path_;
+ CleanUpFunction cleanup_;
+ bool do_cleanup_;
+ bool auto_close_;
+};
+
+} // namespace installd
+} // namespace android
+
+#endif // ANDROID_INSTALLD_UNIQUE_FILE_H