[5/8] mesos git commit: Libprocess: Introduced Hooks for Subprocess.

[jo...@apache.org]

Libprocess: Introduced Hooks for Subprocess.

Review: https://reviews.apache.org/r/43302


Project: http://git-wip-us.apache.org/repos/asf/mesos/repo
Commit: http://git-wip-us.apache.org/repos/asf/mesos/commit/2ed70dc8
Tree: http://git-wip-us.apache.org/repos/asf/mesos/tree/2ed70dc8
Diff: http://git-wip-us.apache.org/repos/asf/mesos/diff/2ed70dc8

Branch: refs/heads/master
Commit: 2ed70dc84771360329482a3b2087a85e21cdfd4a
Parents: 694723f
Author: Joris Van Remoortere <jo...@gmail.com>
Authored: Thu Feb 4 14:54:27 2016 -0500
Committer: Joris Van Remoortere <jo...@gmail.com>
Committed: Wed Feb 10 18:12:05 2016 +0100

----------------------------------------------------------------------
 .../libprocess/include/process/subprocess.hpp   | 27 ++++++++++++++++++++
 3rdparty/libprocess/src/subprocess.cpp          |  5 ++++
 2 files changed, 32 insertions(+)
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http://git-wip-us.apache.org/repos/asf/mesos/blob/2ed70dc8/3rdparty/libprocess/include/process/subprocess.hpp
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diff --git a/3rdparty/libprocess/include/process/subprocess.hpp b/3rdparty/libprocess/include/process/subprocess.hpp
index bb50cc3..c12d1c5 100644
--- a/3rdparty/libprocess/include/process/subprocess.hpp
+++ b/3rdparty/libprocess/include/process/subprocess.hpp
@@ -21,6 +21,7 @@
 
 #include <map>
 #include <memory>
+#include <mutex>
 #include <string>
 #include <vector>
 
@@ -140,6 +141,32 @@ public:
     lambda::function<Try<OutputFileDescriptors>()> output;
   };
 
+  /**
+   * A hook can be passed to a `subprocess` call. It provides a way to
+   * inject dynamic implementation behavior between the clone and exec
+   * calls in the implementation of `subprocess`.
+   */
+  struct Hook
+  {
+    /**
+     * Returns an empty list of hooks.
+     */
+    static std::vector<Hook> None() { return std::vector<Hook>(); }
+
+    Hook(const lambda::function<Try<Nothing>(pid_t)>& _parent_callback);
+
+    /**
+     * The callback that must be sepcified for execution after the
+     * child has been cloned, but before it start executing the new
+     * process. This provides access to the child pid after its
+     * initialization to add tracking or modify execution state of
+     * the child before it executes the new process.
+     */
+    const lambda::function<Try<Nothing>(pid_t)> parent_callback;
+
+    friend class Subprocess;
+  };
+
   // Some syntactic sugar to create an IO::PIPE redirector.
   static IO PIPE();
   static IO PATH(const std::string& path);

http://git-wip-us.apache.org/repos/asf/mesos/blob/2ed70dc8/3rdparty/libprocess/src/subprocess.cpp
----------------------------------------------------------------------
diff --git a/3rdparty/libprocess/src/subprocess.cpp b/3rdparty/libprocess/src/subprocess.cpp
index ff477e3..581fba6 100644
--- a/3rdparty/libprocess/src/subprocess.cpp
+++ b/3rdparty/libprocess/src/subprocess.cpp
@@ -42,6 +42,11 @@ namespace process {
 using InputFileDescriptors = Subprocess::IO::InputFileDescriptors;
 using OutputFileDescriptors = Subprocess::IO::OutputFileDescriptors;
 
+
+Subprocess::Hook::Hook(
+    const lambda::function<Try<Nothing>(pid_t)>& _parent_callback)
+  : parent_callback(_parent_callback) {}
+
 namespace internal {
 
 // See the comment below as to why subprocess is passed to cleanup.