adb: allow reentrant calls to fdevent_run_on_main_thread.
Previously, reentrant calls to fdevent_run_on_main_thread would
deadlock.
Test: adb_test on host
Change-Id: I0783be0558dcaf61ddbe76d13ac6917fc2de0be0
diff --git a/adb/fdevent.cpp b/adb/fdevent.cpp
index b28de4b..d285561 100644
--- a/adb/fdevent.cpp
+++ b/adb/fdevent.cpp
@@ -26,6 +26,7 @@
#include <unistd.h>
#include <atomic>
+#include <deque>
#include <functional>
#include <list>
#include <mutex>
@@ -81,7 +82,7 @@
static auto& run_queue_notify_fd = *new unique_fd();
static auto& run_queue_mutex = *new std::mutex();
-static auto& run_queue GUARDED_BY(run_queue_mutex) = *new std::vector<std::function<void()>>();
+static auto& run_queue GUARDED_BY(run_queue_mutex) = *new std::deque<std::function<void()>>();
void check_main_thread() {
if (main_thread_valid) {
@@ -359,11 +360,21 @@
}
#endif // !ADB_HOST
-static void fdevent_run_flush() REQUIRES(run_queue_mutex) {
- for (auto& f : run_queue) {
- f();
+static void fdevent_run_flush() EXCLUDES(run_queue_mutex) {
+ // We need to be careful around reentrancy here, since a function we call can queue up another
+ // function.
+ while (true) {
+ std::function<void()> fn;
+ {
+ std::lock_guard<std::mutex> lock(run_queue_mutex);
+ if (run_queue.empty()) {
+ break;
+ }
+ fn = run_queue.front();
+ run_queue.pop_front();
+ }
+ fn();
}
- run_queue.clear();
}
static void fdevent_run_func(int fd, unsigned ev, void* /* userdata */) {
@@ -377,22 +388,23 @@
PLOG(FATAL) << "failed to empty run queue notify fd";
}
- std::lock_guard<std::mutex> lock(run_queue_mutex);
fdevent_run_flush();
}
static void fdevent_run_setup() {
- std::lock_guard<std::mutex> lock(run_queue_mutex);
- CHECK(run_queue_notify_fd.get() == -1);
- int s[2];
- if (adb_socketpair(s) != 0) {
- PLOG(FATAL) << "failed to create run queue notify socketpair";
- }
+ {
+ std::lock_guard<std::mutex> lock(run_queue_mutex);
+ CHECK(run_queue_notify_fd.get() == -1);
+ int s[2];
+ if (adb_socketpair(s) != 0) {
+ PLOG(FATAL) << "failed to create run queue notify socketpair";
+ }
- run_queue_notify_fd.reset(s[0]);
- fdevent* fde = fdevent_create(s[1], fdevent_run_func, nullptr);
- CHECK(fde != nullptr);
- fdevent_add(fde, FDE_READ);
+ run_queue_notify_fd.reset(s[0]);
+ fdevent* fde = fdevent_create(s[1], fdevent_run_func, nullptr);
+ CHECK(fde != nullptr);
+ fdevent_add(fde, FDE_READ);
+ }
fdevent_run_flush();
}
diff --git a/adb/fdevent_test.cpp b/adb/fdevent_test.cpp
index 86e0209..63cc4d1 100644
--- a/adb/fdevent_test.cpp
+++ b/adb/fdevent_test.cpp
@@ -194,3 +194,31 @@
ASSERT_EQ(i, vec[i]);
}
}
+
+static std::function<void()> make_appender(std::vector<int>* vec, int value) {
+ return [vec, value]() {
+ check_main_thread();
+ if (value == 100) {
+ return;
+ }
+
+ vec->push_back(value);
+ fdevent_run_on_main_thread(make_appender(vec, value + 1));
+ };
+}
+
+TEST_F(FdeventTest, run_on_main_thread_reentrant) {
+ std::vector<int> vec;
+
+ PrepareThread();
+ std::thread thread(fdevent_loop);
+
+ fdevent_run_on_main_thread(make_appender(&vec, 0));
+
+ TerminateThread(thread);
+
+ ASSERT_EQ(100u, vec.size());
+ for (int i = 0; i < 100; ++i) {
+ ASSERT_EQ(i, vec[i]);
+ }
+}