Multiprocess test client: Android child process launcher rework.

base/posix/global_descriptors.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/posix/global_descriptors.h"
 
 #include <vector>
 #include <utility>
 
 #include "base/logging.h"
+#include "base/rand_util.h"
 
 namespace base {
 
 GlobalDescriptors::Descriptor::Descriptor(Key key, int fd)
     : key(key), fd(fd), region(base::MemoryMappedFile::Region::kWholeFile) {
 }
 
 GlobalDescriptors::Descriptor::Descriptor(Key key,
                                           int fd,
                                           base::MemoryMappedFile::Region region)
@@ skipping 37 matching lines @@
     if (i.key == key) {
       i.fd = fd;
       i.region = region;
       return;
     }
   }
 
   descriptors_.push_back(Descriptor(key, fd, region));
 }
 
+GlobalDescriptors::Key GlobalDescriptors::Register(int fd) {
+  // Find a random unused key.
+  Key key;
+  do {
+    base::RandBytes(&key, sizeof(Key));
+  } while (MaybeGet(key) != -1);
+  Set(key, fd);
+  return key;
+}
+
 base::MemoryMappedFile::Region GlobalDescriptors::GetRegion(Key key) const {
   for (const auto& i : descriptors_) {
     if (i.key == key)
       return i.region;
   }
   DLOG(FATAL) << "Unknown global descriptor: " << key;
   return base::MemoryMappedFile::Region::kWholeFile;
 }
 
 void GlobalDescriptors::Reset(const Mapping& mapping) {
   descriptors_ = mapping;
 }
 
 GlobalDescriptors::GlobalDescriptors() {}
 
 GlobalDescriptors::~GlobalDescriptors() {}
 
 }  // namespace base