PM: CopyVariable can determine whether the source value was set.
CopyVariable is now capable of checking an (optional) flag to see
whether the referenced value is set, instead of blindly copying it. This
preserves the existing interface, which defaults to an "always set"
state. The general interface also accepts a error message that is
returned to the caller of GetValue() in the case where a requested value
was not set.
BUG=None
TEST=Unit tests.
Change-Id: I983ea7b8c3985853cecce7a7b44f208b8b968e21
Reviewed-on: https://chromium-review.googlesource.com/195594
Tested-by: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>
diff --git a/policy_manager/generic_variables.h b/policy_manager/generic_variables.h
index 505b180..261b96c 100644
--- a/policy_manager/generic_variables.h
+++ b/policy_manager/generic_variables.h
@@ -11,6 +11,13 @@
#include "update_engine/policy_manager/variable.h"
+namespace {
+
+const char* kCopyVariableDefaultErrMsg = "Requested value is not set";
+
+} // namespace
+
+
namespace chromeos_policy_manager {
// Variable class returning a copy of a given object using the copy constructor.
@@ -34,29 +41,60 @@
template<typename T>
class CopyVariable : public Variable<T> {
public:
- // Creates the variable returning copies of the passed |obj| reference. The
- // reference to this object is kept and it should be available whenever the
- // GetValue() method is called.
+ // Creates the variable returning copies of the passed |ref|. The reference to
+ // this object is kept and it should be available whenever the GetValue()
+ // method is called. If |is_set_p| is not null, then this flag will be
+ // consulted prior to returning the value, and an |errmsg| will be returned if
+ // it is not set.
+ CopyVariable(const std::string& name, VariableMode mode, const T& ref,
+ const bool* is_set_p, const std::string& errmsg)
+ : Variable<T>(name, mode), ref_(ref), is_set_p_(is_set_p),
+ errmsg_(errmsg) {}
+ CopyVariable(const std::string& name, VariableMode mode, const T& ref,
+ const bool* is_set_p)
+ : CopyVariable(name, mode, ref, is_set_p, kCopyVariableDefaultErrMsg) {}
CopyVariable(const std::string& name, VariableMode mode, const T& ref)
- : Variable<T>(name, mode), ref_(ref) {}
+ : CopyVariable(name, mode, ref, nullptr) {}
+
+ CopyVariable(const std::string& name, const base::TimeDelta poll_interval,
+ const T& ref, const bool* is_set_p, const std::string& errmsg)
+ : Variable<T>(name, poll_interval), ref_(ref), is_set_p_(is_set_p),
+ errmsg_(errmsg) {}
+ CopyVariable(const std::string& name, const base::TimeDelta poll_interval,
+ const T& ref, const bool* is_set_p)
+ : CopyVariable(name, poll_interval, ref, is_set_p,
+ kCopyVariableDefaultErrMsg) {}
CopyVariable(const std::string& name, const base::TimeDelta poll_interval,
const T& ref)
- : Variable<T>(name, poll_interval), ref_(ref) {}
+ : CopyVariable(name, poll_interval, ref, nullptr) {}
protected:
friend class PmCopyVariableTest;
FRIEND_TEST(PmCopyVariableTest, SimpleTest);
+ FRIEND_TEST(PmCopyVariableTest, SetFlagTest);
FRIEND_TEST(PmCopyVariableTest, UseCopyConstructorTest);
// Variable override.
- virtual const T* GetValue(base::TimeDelta /* timeout */,
- std::string* /* errmsg */) {
+ virtual inline const T* GetValue(base::TimeDelta /* timeout */,
+ std::string* errmsg) {
+ if (is_set_p_ && !(*is_set_p_)) {
+ if (errmsg)
+ *errmsg = errmsg_;
+ return nullptr;
+ }
return new T(ref_);
}
private:
// Reference to the object to be copied by GetValue().
const T& ref_;
+
+ // A pointer to a flag indicating whether the value is set. If null, then the
+ // value is assumed to be set.
+ const bool* const is_set_p_;
+
+ // An error message to be returned when attempting to get an unset value.
+ const std::string errmsg_;
};
// Variable class returning a constant value that is cached on the variable when