adb: implement fdevent_set_timeout.

Test: adb_test
Change-Id: I9ae61465617b6a2fe0a1c161ad88c4feae49ec80

adb/fdevent.cpp

@@ -32,6 +32,7 @@
 #include <functional>
 #include <list>
 #include <mutex>
+#include <optional>
 #include <unordered_map>
 #include <utility>
 #include <variant>
@@ -225,14 +226,22 @@ void fdevent_set(fdevent* fde, unsigned events) {
 
 void fdevent_add(fdevent* fde, unsigned events) {
     check_main_thread();
+    CHECK(!(events & FDE_TIMEOUT));
     fdevent_set(fde, (fde->state & FDE_EVENTMASK) | events);
 }
 
 void fdevent_del(fdevent* fde, unsigned events) {
     check_main_thread();
+    CHECK(!(events & FDE_TIMEOUT));
     fdevent_set(fde, (fde->state & FDE_EVENTMASK) & ~events);
 }
 
+void fdevent_set_timeout(fdevent* fde, std::optional<std::chrono::milliseconds> timeout) {
+    check_main_thread();
+    fde->timeout = timeout;
+    fde->last_active = std::chrono::steady_clock::now();
+}
+
 static std::string dump_pollfds(const std::vector<adb_pollfd>& pollfds) {
     std::string result;
     for (const auto& pollfd : pollfds) {
@@ -248,6 +257,32 @@ static std::string dump_pollfds(const std::vector<adb_pollfd>& pollfds) {
     return result;
 }
 
+static std::optional<std::chrono::milliseconds> calculate_timeout() {
+    std::optional<std::chrono::milliseconds> result = std::nullopt;
+    auto now = std::chrono::steady_clock::now();
+    check_main_thread();
+
+    for (const auto& [fd, pollnode] : g_poll_node_map) {
+        UNUSED(fd);
+        auto timeout_opt = pollnode.fde->timeout;
+        if (timeout_opt) {
+            auto deadline = pollnode.fde->last_active + *timeout_opt;
+            auto time_left = std::chrono::duration_cast<std::chrono::milliseconds>(deadline - now);
+            if (time_left < std::chrono::milliseconds::zero()) {
+                time_left = std::chrono::milliseconds::zero();
+            }
+
+            if (!result) {
+                result = time_left;
+            } else {
+                result = std::min(*result, time_left);
+            }
+        }
+    }
+
+    return result;
+}
+
 static void fdevent_process() {
     std::vector<adb_pollfd> pollfds;
     for (const auto& pair : g_poll_node_map) {
@@ -256,11 +291,22 @@ static void fdevent_process() {
     CHECK_GT(pollfds.size(), 0u);
     D("poll(), pollfds = %s", dump_pollfds(pollfds).c_str());
 
-    int ret = adb_poll(&pollfds[0], pollfds.size(), -1);
+    auto timeout = calculate_timeout();
+    int timeout_ms;
+    if (!timeout) {
+        timeout_ms = -1;
+    } else {
+        timeout_ms = timeout->count();
+    }
+
+    int ret = adb_poll(&pollfds[0], pollfds.size(), timeout_ms);
     if (ret == -1) {
         PLOG(ERROR) << "poll(), ret = " << ret;
         return;
     }
+
+    auto post_poll = std::chrono::steady_clock::now();
+
     for (const auto& pollfd : pollfds) {
         if (pollfd.revents != 0) {
             D("for fd %d, revents = %x", pollfd.fd, pollfd.revents);
@@ -282,12 +328,24 @@ static void fdevent_process() {
             events |= FDE_READ | FDE_ERROR;
         }
 #endif
+        auto it = g_poll_node_map.find(pollfd.fd);
+        CHECK(it != g_poll_node_map.end());
+        fdevent* fde = it->second.fde;
+
+        if (events == 0) {
+            // Check for timeout.
+            if (fde->timeout) {
+                auto deadline = fde->last_active + *fde->timeout;
+                if (deadline < post_poll) {
+                    events |= FDE_TIMEOUT;
+                }
+            }
+        }
+
         if (events != 0) {
-            auto it = g_poll_node_map.find(pollfd.fd);
-            CHECK(it != g_poll_node_map.end());
-            fdevent* fde = it->second.fde;
             CHECK_EQ(fde->fd.get(), pollfd.fd);
             fde->events |= events;
+            fde->last_active = post_poll;
             D("%s got events %x", dump_fde(fde).c_str(), events);
             fde->state |= FDE_PENDING;
             g_pending_list.push_back(fde);

adb/fdevent.h

@@ -18,17 +18,20 @@
 #define __FDEVENT_H
 
 #include <stddef.h>
-#include <stdint.h>  /* for int64_t */
+#include <stdint.h>
 
+#include <chrono>
 #include <functional>
+#include <optional>
 #include <variant>
 
 #include "adb_unique_fd.h"
 
-/* events that may be observed */
-#define FDE_READ              0x0001
-#define FDE_WRITE             0x0002
-#define FDE_ERROR             0x0004
+// Events that may be observed
+#define FDE_READ 0x0001
+#define FDE_WRITE 0x0002
+#define FDE_ERROR 0x0004
+#define FDE_TIMEOUT 0x0008
 
 typedef void (*fd_func)(int fd, unsigned events, void *userdata);
 typedef void (*fd_func2)(struct fdevent* fde, unsigned events, void* userdata);
@@ -41,6 +44,8 @@ struct fdevent {
 
     uint16_t state = 0;
     uint16_t events = 0;
+    std::optional<std::chrono::milliseconds> timeout;
+    std::chrono::steady_clock::time_point last_active;
 
     std::variant<fd_func, fd_func2> func;
     void* arg = nullptr;
@@ -62,7 +67,11 @@ void fdevent_set(fdevent *fde, unsigned events);
 void fdevent_add(fdevent *fde, unsigned events);
 void fdevent_del(fdevent *fde, unsigned events);
 
-void fdevent_set_timeout(fdevent *fde, int64_t  timeout_ms);
+// Set a timeout on an fdevent.
+// If no events are triggered by the timeout, an FDE_TIMEOUT will be generated.
+// Note timeouts are not defused automatically; if a timeout is set on an fdevent, it will
+// trigger repeatedly every |timeout| ms.
+void fdevent_set_timeout(fdevent* fde, std::optional<std::chrono::milliseconds> timeout);
 
 // Loop forever, handling events.
 void fdevent_loop();

adb/fdevent_test.cpp

@@ -18,6 +18,7 @@
 
 #include <gtest/gtest.h>
 
+#include <chrono>
 #include <limits>
 #include <memory>
 #include <queue>
@@ -28,6 +29,8 @@
 #include "adb_io.h"
 #include "fdevent_test.h"
 
+using namespace std::chrono_literals;
+
 class FdHandler {
   public:
     FdHandler(int read_fd, int write_fd, bool use_new_callback)
@@ -257,3 +260,100 @@ TEST_F(FdeventTest, run_on_main_thread_reentrant) {
         ASSERT_EQ(i, vec[i]);
     }
 }
+
+TEST_F(FdeventTest, timeout) {
+    fdevent_reset();
+    PrepareThread();
+
+    enum class TimeoutEvent {
+        read,
+        timeout,
+        done,
+    };
+
+    struct TimeoutTest {
+        std::vector<std::pair<TimeoutEvent, std::chrono::steady_clock::time_point>> events;
+        fdevent* fde;
+    };
+    TimeoutTest test;
+
+    int fds[2];
+    ASSERT_EQ(0, adb_socketpair(fds));
+    static constexpr auto delta = 100ms;
+    fdevent_run_on_main_thread([&]() {
+        test.fde = fdevent_create(fds[0], [](fdevent* fde, unsigned events, void* arg) {
+            auto test = static_cast<TimeoutTest*>(arg);
+            auto now = std::chrono::steady_clock::now();
+            CHECK((events & FDE_READ) ^ (events & FDE_TIMEOUT));
+            TimeoutEvent event;
+            if ((events & FDE_READ)) {
+                char buf[2];
+                ssize_t rc = adb_read(fde->fd.get(), buf, sizeof(buf));
+                if (rc == 0) {
+                    event = TimeoutEvent::done;
+                } else if (rc == 1) {
+                    event = TimeoutEvent::read;
+                } else {
+                    abort();
+                }
+            } else if ((events & FDE_TIMEOUT)) {
+                event = TimeoutEvent::timeout;
+            } else {
+                abort();
+            }
+
+            CHECK_EQ(fde, test->fde);
+            test->events.emplace_back(event, now);
+
+            if (event == TimeoutEvent::done) {
+                fdevent_destroy(fde);
+            }
+        }, &test);
+        fdevent_add(test.fde, FDE_READ);
+        fdevent_set_timeout(test.fde, delta);
+    });
+
+    ASSERT_EQ(1, adb_write(fds[1], "", 1));
+
+    // Timeout should happen here
+    std::this_thread::sleep_for(delta);
+
+    // and another.
+    std::this_thread::sleep_for(delta);
+
+    // No timeout should happen here.
+    std::this_thread::sleep_for(delta / 2);
+    adb_close(fds[1]);
+
+    TerminateThread();
+
+    ASSERT_EQ(4ULL, test.events.size());
+    ASSERT_EQ(TimeoutEvent::read, test.events[0].first);
+    ASSERT_EQ(TimeoutEvent::timeout, test.events[1].first);
+    ASSERT_EQ(TimeoutEvent::timeout, test.events[2].first);
+    ASSERT_EQ(TimeoutEvent::done, test.events[3].first);
+
+    std::vector<int> time_deltas;
+    for (size_t i = 0; i < test.events.size() - 1; ++i) {
+        auto before = test.events[i].second;
+        auto after = test.events[i + 1].second;
+        auto diff = std::chrono::duration_cast<std::chrono::milliseconds>(after - before);
+        time_deltas.push_back(diff.count());
+    }
+
+    std::vector<int> expected = {
+        delta.count(),
+        delta.count(),
+        delta.count() / 2,
+    };
+
+    std::vector<int> diff;
+    ASSERT_EQ(time_deltas.size(), expected.size());
+    for (size_t i = 0; i < time_deltas.size(); ++i) {
+        diff.push_back(std::abs(time_deltas[i] - expected[i]));
+    }
+
+    ASSERT_LT(diff[0], delta.count() * 0.5);
+    ASSERT_LT(diff[1], delta.count() * 0.5);
+    ASSERT_LT(diff[2], delta.count() * 0.5);
+}

adb/sysdeps/chrono.h

@@ -18,29 +18,4 @@
 
 #include <chrono>
 
-#if defined(_WIN32)
-// We don't have C++14 on Windows yet.
-// Reimplement std::chrono_literals ourselves until we do.
-
-// Silence the following warning (which gets promoted to an error):
-// error: literal operator suffixes not preceded by ‘_’ are reserved for future standardization
-#pragma GCC system_header
-
-constexpr std::chrono::seconds operator"" s(unsigned long long s) {
-    return std::chrono::seconds(s);
-}
-
-constexpr std::chrono::duration<long double> operator"" s(long double s) {
-    return std::chrono::duration<long double>(s);
-}
-
-constexpr std::chrono::milliseconds operator"" ms(unsigned long long ms) {
-    return std::chrono::milliseconds(ms);
-}
-
-constexpr std::chrono::duration<long double, std::milli> operator"" ms(long double ms) {
-    return std::chrono::duration<long double, std::milli>(ms);
-}
-#else
 using namespace std::chrono_literals;
-#endif