From 5773b08cf8709a2b8642f45b5e2f5560df332e22 Mon Sep 17 00:00:00 2001
From: Michael Carlberg <c@rlberg.se>
Date: Wed, 11 Jan 2017 18:15:46 +0100
Subject: [PATCH] fix(script): Poll file descriptors

---
 include/utils/io.hpp   |  6 +++---
 src/modules/script.cpp | 25 +++++++++++++++----------
 src/utils/io.cpp       |  2 +-
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/include/utils/io.hpp b/include/utils/io.hpp
index 8360172d..921e9d12 100644
--- a/include/utils/io.hpp
+++ b/include/utils/io.hpp
@@ -14,9 +14,9 @@ namespace io_util {
   void tail(int read_fd, const function<void(string)>& callback);
   void tail(int read_fd, int writeback_fd);
 
-  bool poll(int fd, short int events, int timeout_ms = 1);
-  bool poll_read(int fd, int timeout_ms = 1);
-  bool poll_write(int fd, int timeout_ms = 1);
+  bool poll(int fd, short int events, int timeout_ms = 0);
+  bool poll_read(int fd, int timeout_ms = 0);
+  bool poll_write(int fd, int timeout_ms = 0);
 
   bool interrupt_read(int write_fd);
 
diff --git a/src/modules/script.cpp b/src/modules/script.cpp
index 6c641904..8a334305 100644
--- a/src/modules/script.cpp
+++ b/src/modules/script.cpp
@@ -1,6 +1,5 @@
 #include "modules/script.hpp"
 #include "drawtypes/label.hpp"
-
 #include "modules/meta/base.inl"
 
 POLYBAR_NS
@@ -31,14 +30,19 @@ namespace modules {
               }
             }
 
-            if (io_util::poll(m_command->get_stdout(PIPE_READ), POLLIN, 0)) {
-              if ((m_output = m_command->readline()) != m_prev) {
+            int fd = m_command->get_stdout(PIPE_READ);
+            while (!m_stopping && fd != -1 && m_command->is_running() && !io_util::poll(fd, POLLHUP, 0)) {
+              if (!io_util::poll_read(fd, 25)) {
+                continue;
+              } else if ((m_output = m_command->readline()) != m_prev) {
                 m_prev = m_output;
                 broadcast();
               }
             }
 
-            if (m_command && !m_command->is_running()) {
+            if (m_stopping) {
+              return chrono::duration<double>{0};
+            } else if (m_command && !m_command->is_running()) {
               return std::max(m_command->get_exit_status() == 0 ? m_interval : 1s, m_interval);
             } else {
               return m_interval;
@@ -60,9 +64,14 @@ namespace modules {
             throw module_error("Failed to execute command, stopping module...");
           }
 
-          if ((m_output = m_command->readline()) != m_prev) {
+          int fd = m_command->get_stdout(PIPE_READ);
+          if (fd != -1 && io_util::poll_read(fd) && (m_output = m_command->readline()) != m_prev) {
             broadcast();
             m_prev = m_output;
+          } else if (m_command->get_exit_status() != 0) {
+            m_output.clear();
+            m_prev.clear();
+            broadcast();
           }
 
           return std::max(m_command->get_exit_status() == 0 ? m_interval : 1s, m_interval);
@@ -114,14 +123,10 @@ namespace modules {
    * Stop the module worker by terminating any running commands
    */
   void script_module::stop() {
-    std::lock_guard<decltype(m_handler)> guard(m_handler);
     m_stopping = true;
     wakeup();
 
-    if (m_command && m_command->is_running()) {
-      m_log.warn("%s: Stopping shell command", name());
-      m_command->terminate();
-    }
+    std::lock_guard<decltype(m_handler)> guard(m_handler);
 
     m_command.reset();
     module::stop();
diff --git a/src/utils/io.cpp b/src/utils/io.cpp
index f0c22d2e..8e3dc017 100644
--- a/src/utils/io.cpp
+++ b/src/utils/io.cpp
@@ -73,7 +73,7 @@ namespace io_util {
   }
 
   bool interrupt_read(int write_fd) {
-    return writeline(write_fd, "") > 0;
+    return write(write_fd, 1, {'\n'}) > 0;
   }
 
   void set_block(int fd) {