move MemoryMapping, Shell, ThreadId, ThreadName, and VersionCheck to system/

[folly.git] / folly / system / Shell.h

diff --git a/folly/system/Shell.h b/folly/system/Shell.h
new file mode 100644 (file)
index 0000000..cefe2dd
--- /dev/null
+++ b/folly/system/Shell.h
@@ -0,0 +1,93 @@
+/*
+ * Copyright 2017 Facebook, Inc.
+ *
+ * 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.
+ */
+
+/**
+ * `Shell` provides a collection of functions to use with `Subprocess` that make
+ * it easier to safely run processes in a unix shell.
+ *
+ * Note: use this rarely and carefully. By default you should use `Subprocess`
+ * with a vector of arguments.
+ */
+
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include <folly/Conv.h>
+#include <folly/Format.h>
+#include <folly/Range.h>
+
+namespace folly {
+
+/**
+ * Quotes an argument to make it suitable for use as shell command arguments.
+ */
+std::string shellQuote(StringPiece argument);
+
+namespace detail {
+template <typename... Arguments>
+std::vector<std::string> shellify(
+    StringPiece format,
+    Arguments&&... arguments) {
+  auto command = sformat(
+      format,
+      shellQuote(to<std::string>(std::forward<Arguments>(arguments)))...);
+  return {"/bin/sh", "-c", command};
+}
+
+struct ShellCmdFormat {
+  StringPiece format;
+  template <typename... Arguments>
+  std::vector<std::string> operator()(Arguments&&... arguments) const {
+    return ::folly::detail::shellify(
+        format, std::forward<Arguments>(arguments)...);
+  }
+};
+
+} // namespace detail
+
+inline namespace literals {
+inline namespace shell_literals {
+constexpr detail::ShellCmdFormat operator"" _shellify(
+    char const* name,
+    std::size_t length) {
+  return {folly::StringPiece(name, length)};
+}
+} // inline namespace shell_literals
+} // inline namespace literals
+
+/**
+  * Create argument array for `Subprocess()` for a process running in a
+  * shell.
+  *
+  * The shell to use is always going to be `/bin/sh`.
+  *
+  * This is deprecated in favour of the user-defined-literal `_shellify`
+  * from namespace `folly::shell_literals` because that requires that the format
+  * string is a compile-time constant which can be inspected during code reviews
+  */
+template <typename... Arguments>
+FOLLY_DEPRECATED(
+    "Use `\"command {} {} ...\"_shellify(argument1, argument2 ...)` from "
+    "namespace `folly::literals::shell_literals`")
+std::vector<std::string> shellify(
+    StringPiece format,
+    Arguments&&... arguments) {
+  return detail::shellify(format, std::forward<Arguments>(arguments)...);
+}
+
+} // namespace folly