media: Add static MojoCdmService::GetCdm().

media/mojo/services/mojo_cdm_service.cc

Index: media/mojo/services/mojo_cdm_service.cc
diff --git a/media/mojo/services/mojo_cdm_service.cc b/media/mojo/services/mojo_cdm_service.cc
index 4a163872305d5572e6c6abd2a1fb8716976c321f..981ec4d485a442a5f03e2b3621484994f21cf3ad 100644
--- a/media/mojo/services/mojo_cdm_service.cc
+++ b/media/mojo/services/mojo_cdm_service.cc
@@ -4,7 +4,10 @@
 
 #include "media/mojo/services/mojo_cdm_service.h"
 
+#include <map>
+
 #include "base/bind.h"
+#include "base/lazy_instance.h"
 #include "media/base/cdm_config.h"
 #include "media/base/cdm_context.h"
 #include "media/base/cdm_factory.h"
@@ -18,12 +21,31 @@
 
 namespace media {
 
+namespace {
+
+// A static map between the CDM ID and the CDM. Can be accessed on different
+// threads (protected by the |g_cdm_map_lock_|).
+using CdmMap = std::map<int, scoped_refptr<MediaKeys>>;
+
+base::LazyInstance<CdmMap>::Leaky g_cdm_map = LAZY_INSTANCE_INITIALIZER;

[DaleCurtis, 2015/11/17 23:57:05]

Instead of two lazy instances you could put this in a class that returns the id
based on an internal lock?

[xhwang, 2015/11/18 00:52:53]

It does make the main impl (MojoCdmService) cleaner. Done!

+
+base::LazyInstance<base::Lock>::Leaky g_cdm_map_lock =
+    LAZY_INSTANCE_INITIALIZER;
+}
+
 using SimpleMojoCdmPromise = MojoCdmPromise<>;
 using CdmIdMojoCdmPromise = MojoCdmPromise<int>;
 using NewSessionMojoCdmPromise = MojoCdmPromise<std::string>;
 
 int MojoCdmService::next_cdm_id_ = CdmContext::kInvalidCdmId + 1;
 
+// static
+scoped_refptr<MediaKeys> MojoCdmService::GetCdm(int cdm_id) {
+  DVLOG(1) << __FUNCTION__ << ": " << cdm_id;
+  base::AutoLock lock(g_cdm_map_lock.Get());
+  return g_cdm_map.Get().count(cdm_id) ? g_cdm_map.Get()[cdm_id] : nullptr;
+}
+
 MojoCdmService::MojoCdmService(
     base::WeakPtr<MojoCdmServiceContext> context,
     mojo::ServiceProvider* service_provider,
@@ -40,6 +62,12 @@ MojoCdmService::MojoCdmService(
 }
 
 MojoCdmService::~MojoCdmService() {
+  {
+    base::AutoLock lock(g_cdm_map_lock.Get());
+    DCHECK(g_cdm_map.Get().count(cdm_id_));
+    g_cdm_map.Get().erase(cdm_id_);
+  }
+
   if (cdm_id_ != CdmContext::kInvalidCdmId && context_)
     context_->UnregisterCdm(cdm_id_);
 }
@@ -152,6 +180,14 @@ void MojoCdmService::OnCdmCreated(scoped_ptr<CdmIdMojoCdmPromise> promise,
   cdm_ = cdm;
   cdm_id_ = next_cdm_id_++;
   context_->RegisterCdm(cdm_id_, this);
+
+  {
+    base::AutoLock lock(g_cdm_map_lock.Get());
+    DCHECK(!g_cdm_map.Get().count(cdm_id_));
+    g_cdm_map.Get()[cdm_id_] = cdm;
+  }
+
+  DVLOG(1) << __FUNCTION__ << ": CDM successfully created with ID " << cdm_id_;
   promise->resolve(cdm_id_);
 }