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Merge "Fix timeouts for android::base::WaitForProperty*"

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This commit is contained in:
Tom Cherry 2017-03-28 20:38:23 +00:00 committed by Gerrit Code Review
commit 57d78354d6
3 changed files with 51 additions and 23 deletions
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9
base/include/android-base/properties.h
View file

@ -62,15 +62,14 @@ bool SetProperty(const std::string& key, const std::string& value);
// Waits for the system property `key` to have the value `expected_value`.
// Times out after `relative_timeout`.
// Returns true on success, false on timeout.
bool WaitForProperty(const std::string& key,
const std::string& expected_value,
std::chrono::milliseconds relative_timeout);
bool WaitForProperty(const std::string& key, const std::string& expected_value,
std::chrono::milliseconds relative_timeout = std::chrono::milliseconds::max());
// Waits for the system property `key` to be created.
// Times out after `relative_timeout`.
// Returns true on success, false on timeout.
bool WaitForPropertyCreation(const std::string& key,
std::chrono::milliseconds relative_timeout);
bool WaitForPropertyCreation(const std::string& key, std::chrono::milliseconds relative_timeout =
std::chrono::milliseconds::max());
} // namespace base
} // namespace android

33
base/properties.cpp
View file

@ -101,22 +101,24 @@ static void WaitForPropertyCallback(void* data_ptr, const char*, const char* val
}
// TODO: chrono_utils?
static void DurationToTimeSpec(timespec& ts, std::chrono::nanoseconds d) {
static void DurationToTimeSpec(timespec& ts, const std::chrono::milliseconds d) {
auto s = std::chrono::duration_cast<std::chrono::seconds>(d);
auto ns = std::chrono::duration_cast<std::chrono::nanoseconds>(d - s);
ts.tv_sec = s.count();
ts.tv_nsec = ns.count();
}
// TODO: boot_clock?
using AbsTime = std::chrono::time_point<std::chrono::steady_clock>;
static void UpdateTimeSpec(timespec& ts,
const AbsTime& timeout) {
static void UpdateTimeSpec(timespec& ts, std::chrono::milliseconds relative_timeout,
const AbsTime& start_time) {
auto now = std::chrono::steady_clock::now();
auto remaining_timeout = std::chrono::duration_cast<std::chrono::nanoseconds>(timeout - now);
if (remaining_timeout < 0ns) {
auto time_elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(now - start_time);
if (time_elapsed >= relative_timeout) {
ts = { 0, 0 };
} else {
auto remaining_timeout = relative_timeout - time_elapsed;
DurationToTimeSpec(ts, remaining_timeout);
}
}
@ -127,11 +129,7 @@ static void UpdateTimeSpec(timespec& ts,
// Returns nullptr on timeout.
static const prop_info* WaitForPropertyCreation(const std::string& key,
const std::chrono::milliseconds& relative_timeout,
AbsTime& absolute_timeout) {
// TODO: boot_clock?
auto now = std::chrono::steady_clock::now();
absolute_timeout = now + relative_timeout;
const AbsTime& start_time) {
// Find the property's prop_info*.
const prop_info* pi;
unsigned global_serial = 0;
@ -139,17 +137,16 @@ static const prop_info* WaitForPropertyCreation(const std::string& key,
// The property doesn't even exist yet.
// Wait for a global change and then look again.
timespec ts;
UpdateTimeSpec(ts, absolute_timeout);
UpdateTimeSpec(ts, relative_timeout, start_time);
if (!__system_property_wait(nullptr, global_serial, &global_serial, &ts)) return nullptr;
}
return pi;
}
bool WaitForProperty(const std::string& key,
const std::string& expected_value,
bool WaitForProperty(const std::string& key, const std::string& expected_value,
std::chrono::milliseconds relative_timeout) {
AbsTime absolute_timeout;
const prop_info* pi = WaitForPropertyCreation(key, relative_timeout, absolute_timeout);
auto start_time = std::chrono::steady_clock::now();
const prop_info* pi = WaitForPropertyCreation(key, relative_timeout, start_time);
if (pi == nullptr) return false;
WaitForPropertyData data;
@ -162,7 +159,7 @@ bool WaitForProperty(const std::string& key,
if (data.done) return true;
// It didn't, so wait for the property to change before checking again.
UpdateTimeSpec(ts, absolute_timeout);
UpdateTimeSpec(ts, relative_timeout, start_time);
uint32_t unused;
if (!__system_property_wait(pi, data.last_read_serial, &unused, &ts)) return false;
}
@ -170,8 +167,8 @@ bool WaitForProperty(const std::string& key,
bool WaitForPropertyCreation(const std::string& key,
std::chrono::milliseconds relative_timeout) {
AbsTime absolute_timeout;
return (WaitForPropertyCreation(key, relative_timeout, absolute_timeout) != nullptr);
auto start_time = std::chrono::steady_clock::now();
return (WaitForPropertyCreation(key, relative_timeout, start_time) != nullptr);
}
} // namespace base

32
base/properties_test.cpp
View file

@ -151,6 +151,38 @@ TEST(properties, WaitForProperty_timeout) {
ASSERT_LT(std::chrono::duration_cast<std::chrono::milliseconds>(t1 - t0), 600ms);
}
TEST(properties, WaitForProperty_MaxTimeout) {
std::atomic<bool> flag{false};
std::thread thread([&]() {
android::base::SetProperty("debug.libbase.WaitForProperty_test", "a");
while (!flag) std::this_thread::yield();
std::this_thread::sleep_for(500ms);
android::base::SetProperty("debug.libbase.WaitForProperty_test", "b");
});
ASSERT_TRUE(android::base::WaitForProperty("debug.libbase.WaitForProperty_test", "a", 1s));
flag = true;
// Test that this does not immediately return false due to overflow issues with the timeout.
ASSERT_TRUE(android::base::WaitForProperty("debug.libbase.WaitForProperty_test", "b"));
thread.join();
}
TEST(properties, WaitForProperty_NegativeTimeout) {
std::atomic<bool> flag{false};
std::thread thread([&]() {
android::base::SetProperty("debug.libbase.WaitForProperty_test", "a");
while (!flag) std::this_thread::yield();
std::this_thread::sleep_for(500ms);
android::base::SetProperty("debug.libbase.WaitForProperty_test", "b");
});
ASSERT_TRUE(android::base::WaitForProperty("debug.libbase.WaitForProperty_test", "a", 1s));
flag = true;
// Assert that this immediately returns with a negative timeout
ASSERT_FALSE(android::base::WaitForProperty("debug.libbase.WaitForProperty_test", "b", -100ms));
thread.join();
}
TEST(properties, WaitForPropertyCreation) {
std::thread thread([&]() {
std::this_thread::sleep_for(100ms);