Reopen pipe path on EOF

include/components/eventloop.hpp

@@ -40,6 +40,10 @@ struct UVHandleGeneric {
     close();
   }
 
+  uv_loop_t* loop() const {
+    return handle->loop;
+  }
+
   void close() {
     if (handle && !uv_is_closing((uv_handle_t*)handle)) {
       uv_close((uv_handle_t*)handle, close_callback);
@@ -91,15 +95,16 @@ struct FSEventHandle : public UVHandle<uv_fs_event_t, const char*, int, int> {
 };
 
 struct PipeHandle : public UVHandleGeneric<uv_pipe_t, uv_stream_t, ssize_t, const uv_buf_t*> {
-  PipeHandle(
-      uv_loop_t* loop, function<void(const string)> fun, function<void(void)> eof_cb, function<void(int)> err_cb);
-  void start(int fd);
+  PipeHandle(uv_loop_t* loop, const string& path, function<void(const string)> fun, function<void(void)> eof_cb,
+      function<void(int)> err_cb);
+  void start();
   void read_cb(ssize_t nread, const uv_buf_t* buf);
 
   function<void(const string)> func;
   function<void(void)> eof_cb;
   function<void(int)> err_cb;
   int fd;
+  string path;
 };
 
 struct TimerHandle : public UVHandle<uv_timer_t> {
@@ -129,7 +134,8 @@ class eventloop {
   void signal_handle(int signum, function<void(int)> fun);
   void poll_handle(int events, int fd, function<void(uv_poll_event)> fun, function<void(int)> err_cb);
   void fs_event_handle(const string& path, function<void(const char*, uv_fs_event)> fun, function<void(int)> err_cb);
-  void pipe_handle(int fd, function<void(const string)> fun, function<void(void)> eof_cb, function<void(int)> err_cb);
+  void pipe_handle(
+      const string& path, function<void(const string)> fun, function<void(void)> eof_cb, function<void(int)> err_cb);
   void timer_handle(uint64_t timeout, uint64_t repeat, function<void(void)> fun);
   AsyncHandle_t async_handle(function<void(void)> fun);
 

include/components/ipc.hpp

@@ -26,16 +26,16 @@ class ipc {
   explicit ipc(signal_emitter& emitter, const logger& logger);
   ~ipc();
 
+  string get_path() const;
+
   void receive_data(string buf);
   void receive_eof();
-  int get_file_descriptor() const;
 
  private:
   signal_emitter& m_sig;
   const logger& m_log;
 
   string m_path{};
-  int m_fd;
 
   /**
    * Buffer for the currently received IPC message.

src/components/controller.cpp

@@ -260,7 +260,7 @@ void controller::read_events(bool confwatch) {
 
     if (m_ipc) {
       eloop->pipe_handle(
-          m_ipc->get_file_descriptor(), [this](const string payload) { m_ipc->receive_data(payload); },
+          m_ipc->get_path(), [this](const string payload) { m_ipc->receive_data(payload); },
           [this]() { m_ipc->receive_eof(); },
           [this](int err) { m_log.err("libuv error while listening to IPC channel: %s", uv_strerror(err)); });
     }

src/components/eventloop.cpp

@@ -2,6 +2,8 @@
 
 #include <cassert>
 
+#include "errors.hpp"
+
 POLYBAR_NS
 
 /**
@@ -95,37 +97,54 @@ void FSEventHandle::fs_event_cb(const char* path, int events, int status) {
 // }}}
 
 // PipeHandle {{{
-PipeHandle::PipeHandle(
-    uv_loop_t* loop, function<void(const string)> fun, function<void(void)> eof_cb, function<void(int)> err_cb)
+PipeHandle::PipeHandle(uv_loop_t* loop, const string& path, function<void(const string)> fun,
+    function<void(void)> eof_cb, function<void(int)> err_cb)
     : UVHandleGeneric([&](ssize_t nread, const uv_buf_t* buf) { read_cb(nread, buf); })
     , func(fun)
     , eof_cb(eof_cb)
-    , err_cb(err_cb) {
+    , err_cb(err_cb)
+    , path(path) {
   UV(uv_pipe_init, loop, handle, false);
 }
 
-void PipeHandle::start(int fd) {
-  this->fd = fd;
+void PipeHandle::start() {
+  if ((fd = open(path.c_str(), O_RDONLY | O_NONBLOCK)) == -1) {
+    throw system_error("Failed to open pipe '" + path + "'");
+  }
   UV(uv_pipe_open, handle, fd);
   UV(uv_read_start, (uv_stream_t*)handle, alloc_cb, callback);
 }
 
 void PipeHandle::read_cb(ssize_t nread, const uv_buf_t* buf) {
+  /*
+   * Wrap pointer so that it gets automatically freed once the function returns (even with exceptions)
+   */
+  auto buf_ptr = unique_ptr<char>(buf->base);
   if (nread > 0) {
-    func(string(buf->base, nread));
+    func(string(buf_ptr.get(), nread));
   } else if (nread < 0) {
     if (nread != UV_EOF) {
       close();
       err_cb(nread);
     } else {
       eof_cb();
-      // TODO this causes constant EOFs
-      start(this->fd);
-    }
-  }
 
-  if (buf->base) {
-    delete[] buf->base;
+      /*
+       * This is a special case.
+       *
+       * Once we read EOF, we no longer receive events for the fd, so we close the entire handle and restart it with a
+       * new fd.
+       *
+       * We reuse the memory for the underlying uv handle
+       */
+      if (!uv_is_closing((uv_handle_t*)handle)) {
+        uv_close((uv_handle_t*)handle, [](uv_handle_t* handle) {
+          PipeHandle* This = static_cast<PipeHandle*>(handle->data);
+          UV(uv_pipe_init, This->loop(), This->handle, false);
+          This->start();
+        });
+      }
+    }
   }
 }
 // }}}
@@ -215,9 +234,9 @@ void eventloop::fs_event_handle(
 }
 
 void eventloop::pipe_handle(
-    int fd, function<void(const string)> fun, function<void(void)> eof_cb, function<void(int)> err_cb) {
-  m_pipe_handles.emplace_back(std::make_unique<PipeHandle>(get(), fun, eof_cb, err_cb));
-  m_pipe_handles.back()->start(fd);
+    const string& path, function<void(const string)> fun, function<void(void)> eof_cb, function<void(int)> err_cb) {
+  m_pipe_handles.emplace_back(std::make_unique<PipeHandle>(get(), path, fun, eof_cb, err_cb));
+  m_pipe_handles.back()->start();
 }
 
 void eventloop::timer_handle(uint64_t timeout, uint64_t repeat, function<void(void)> fun) {

src/components/ipc.cpp

@@ -39,11 +39,6 @@ ipc::ipc(signal_emitter& emitter, const logger& logger) : m_sig(emitter), m_log(
   if (mkfifo(m_path.c_str(), 0666) == -1) {
     throw system_error("Failed to create ipc channel");
   }
-
-  if ((m_fd = open(m_path.c_str(), O_RDONLY | O_NONBLOCK)) == -1) {
-    throw system_error("Failed to open pipe '" + m_path + "'");
-  }
-
   m_log.info("Created ipc channel at: %s", m_path);
 }
 
@@ -51,10 +46,12 @@ ipc::ipc(signal_emitter& emitter, const logger& logger) : m_sig(emitter), m_log(
  * Deconstruct ipc handler
  */
 ipc::~ipc() {
-  if (!m_path.empty()) {
-    m_log.trace("ipc: Removing file handle");
-    unlink(m_path.c_str());
-  }
+  m_log.trace("ipc: Removing file handle at: %s", m_path);
+  unlink(m_path.c_str());
+}
+
+string ipc::get_path() const {
+  return m_path;
 }
 
 /**
@@ -87,11 +84,4 @@ void ipc::receive_eof() {
   }
 }
 
-/**
- * Get the file descriptor to the ipc channel
- */
-int ipc::get_file_descriptor() const {
-  return m_fd;
-}
-
 POLYBAR_NS_END