Revert "Revert "Create libbase.""
This reverts commit a7870d88167f619e758b5bcd15b410d16da7c16b.
diff --git a/base/file.cpp b/base/file.cpp
new file mode 100644
index 0000000..773f33b
--- /dev/null
+++ b/base/file.cpp
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2015 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.
+ */
+
+#include "base/file.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <string>
+
+#define LOG_TAG "base.file"
+#include "cutils/log.h"
+#include "utils/Compat.h" // For TEMP_FAILURE_RETRY on Darwin.
+
+namespace android {
+namespace base {
+
+bool ReadFdToString(int fd, std::string* content) {
+ content->clear();
+
+ char buf[BUFSIZ];
+ ssize_t n;
+ while ((n = TEMP_FAILURE_RETRY(read(fd, &buf[0], sizeof(buf)))) > 0) {
+ content->append(buf, n);
+ }
+ return (n == 0) ? true : false;
+}
+
+bool ReadFileToString(const std::string& path, std::string* content) {
+ content->clear();
+
+ int fd =
+ TEMP_FAILURE_RETRY(open(path.c_str(), O_RDONLY | O_CLOEXEC | O_NOFOLLOW));
+ if (fd == -1) {
+ return false;
+ }
+ bool result = ReadFdToString(fd, content);
+ TEMP_FAILURE_RETRY(close(fd));
+ return result;
+}
+
+bool WriteStringToFd(const std::string& content, int fd) {
+ const char* p = content.data();
+ size_t left = content.size();
+ while (left > 0) {
+ ssize_t n = TEMP_FAILURE_RETRY(write(fd, p, left));
+ if (n == -1) {
+ return false;
+ }
+ p += n;
+ left -= n;
+ }
+ return true;
+}
+
+static bool CleanUpAfterFailedWrite(const std::string& path) {
+ // Something went wrong. Let's not leave a corrupt file lying around.
+ int saved_errno = errno;
+ unlink(path.c_str());
+ errno = saved_errno;
+ return false;
+}
+
+#if !defined(_WIN32)
+bool WriteStringToFile(const std::string& content, const std::string& path,
+ mode_t mode, uid_t owner, gid_t group) {
+ int fd = TEMP_FAILURE_RETRY(
+ open(path.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NOFOLLOW,
+ mode));
+ if (fd == -1) {
+ ALOGE("android::WriteStringToFile open failed: %s", strerror(errno));
+ return false;
+ }
+
+ // We do an explicit fchmod here because we assume that the caller really
+ // meant what they said and doesn't want the umask-influenced mode.
+ if (fchmod(fd, mode) == -1) {
+ ALOGE("android::WriteStringToFile fchmod failed: %s", strerror(errno));
+ return CleanUpAfterFailedWrite(path);
+ }
+ if (fchown(fd, owner, group) == -1) {
+ ALOGE("android::WriteStringToFile fchown failed: %s", strerror(errno));
+ return CleanUpAfterFailedWrite(path);
+ }
+ if (!WriteStringToFd(content, fd)) {
+ ALOGE("android::WriteStringToFile write failed: %s", strerror(errno));
+ return CleanUpAfterFailedWrite(path);
+ }
+ TEMP_FAILURE_RETRY(close(fd));
+ return true;
+}
+#endif
+
+bool WriteStringToFile(const std::string& content, const std::string& path) {
+ int fd = TEMP_FAILURE_RETRY(
+ open(path.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NOFOLLOW,
+ DEFFILEMODE));
+ if (fd == -1) {
+ return false;
+ }
+
+ bool result = WriteStringToFd(content, fd);
+ TEMP_FAILURE_RETRY(close(fd));
+ return result || CleanUpAfterFailedWrite(path);
+}
+
+} // namespace base
+} // namespace android