[Tarantool-patches] [PATCH 12/13] coio: add *_noxc read / write functions

[Alexander Turenko]

The popen implementation is written in C and uses coio read / write
functions. If an exception occurs, it'll pass through the C code. It
should be catched to proceed correctly.

We usually have foo() and foo_xc() (exception) functions when both
variants are necessary. Here I added non-conventional *_noxc() functions
as the temporary solution to postpone refactoring of the code and all
its usages.

Part of #4031
---
 src/lib/core/coio.cc | 39 +++++++++++++++++++++++++++++++++++++++
 src/lib/core/coio.h  | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 80 insertions(+)

diff --git a/src/lib/core/coio.cc b/src/lib/core/coio.cc
index 74e6240ce..6a113aa47 100644
--- a/src/lib/core/coio.cc
+++ b/src/lib/core/coio.cc
@@ -381,6 +381,26 @@ coio_readn_ahead_timeout(struct ev_io *coio, void *buf, size_t sz, size_t bufsiz
 	return nrd;
 }
 
+/*
+ * FIXME: Rewrite coio_read_ahead_timeout() w/o C++ exceptions and
+ * drop this function.
+ */
+ssize_t
+coio_read_ahead_timeout_noxc(struct ev_io *coio, void *buf, size_t sz,
+			     size_t bufsiz, ev_tstamp timeout)
+{
+	try {
+		return coio_read_ahead_timeout(coio, buf, sz, bufsiz, timeout);
+	} catch (Exception *) {
+		/*
+		 * The exception is already in the diagnostics
+		 * area. Nothing to do.
+		 */
+	}
+	return -1;
+}
+
+
 /** Write sz bytes to socket.
  *
  * Throws SocketError in case of write error. If
@@ -437,6 +457,25 @@ coio_write_timeout(struct ev_io *coio, const void *buf, size_t sz,
 	}
 }
 
+/*
+ * FIXME: Rewrite coio_write_timeout() w/o C++ exceptions and drop
+ * this function.
+ */
+ssize_t
+coio_write_timeout_noxc(struct ev_io *coio, const void *buf, size_t sz,
+			ev_tstamp timeout)
+{
+	try {
+		return coio_write_timeout(coio, buf, sz, timeout);
+	} catch (Exception *) {
+		/*
+		 * The exception is already in the diagnostics
+		 * area. Nothing to do.
+		 */
+	}
+	return -1;
+}
+
 /*
  * Write iov using sio API.
  * Put in an own function to workaround gcc bug with @finally
diff --git a/src/lib/core/coio.h b/src/lib/core/coio.h
index c323955d7..7875a0da1 100644
--- a/src/lib/core/coio.h
+++ b/src/lib/core/coio.h
@@ -130,6 +130,29 @@ coio_read_timeout(struct ev_io *coio, void *buf, size_t sz, ev_tstamp timeout)
 	return coio_read_ahead_timeout(coio, buf, sz, sz, timeout);
 }
 
+/**
+ * Read data with timeout.
+ *
+ * Yield until some data will be available for read.
+ *
+ * Returns amount of read bytes at success, otherwise returns -1
+ * and set a diag.
+ *
+ * Zero return value means EOF.
+ *
+ * Note: Less then @a count bytes may be available for read at a
+ * moment, so a return value less then @a count does not mean EOF.
+ *
+ * Possible errors:
+ *
+ * - SocketError: an IO error occurs at read().
+ * - TimedOut: @a timeout quota is exceeded.
+ * - FiberIsCancelled: cancelled by an outside code.
+ */
+ssize_t
+coio_read_ahead_timeout_noxc(struct ev_io *coio, void *buf, size_t sz,
+			     size_t bufsiz, ev_tstamp timeout);
+
 static inline ssize_t
 coio_readn(struct ev_io *coio, void *buf, size_t sz)
 {
@@ -144,6 +167,24 @@ ssize_t
 coio_write_timeout(struct ev_io *coio, const void *buf, size_t sz,
 		   ev_tstamp timeout);
 
+/**
+ * Write @a count bytes with timeout.
+ *
+ * Yield until all @a count bytes will be written.
+ *
+ * Returns @a count at success, otherwise returns -1 and set a
+ * diag.
+ *
+ * Possible errors:
+ *
+ * - SocketError: an IO error occurs at write().
+ * - TimedOut: @a timeout quota is exceeded.
+ * - FiberIsCancelled: cancelled by an outside code.
+ */
+ssize_t
+coio_write_timeout_noxc(struct ev_io *coio, const void *buf, size_t sz,
+			ev_tstamp timeout);
+
 static inline void
 coio_write(struct ev_io *coio, const void *buf, size_t sz)
 {
-- 
2.25.0