[Spice-devel] [PATCH spice-streaming-agent v4 1/4] Use exception handling data from streaming device

[Frediano Ziglio]

In all paths errors from this function are treated like fatal
error, there's no need to handle all manually potentially
forgetting to handle errors.
Also avoid to deal directly with logging moving the responsibility
to other layers.

Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
---
 src/spice-streaming-agent.cpp | 35 ++++++++++++++---------------------
 1 file changed, 14 insertions(+), 21 deletions(-)

diff --git a/src/spice-streaming-agent.cpp b/src/spice-streaming-agent.cpp
index 1f41a6f..5613934 100644
--- a/src/spice-streaming-agent.cpp
+++ b/src/spice-streaming-agent.cpp
@@ -77,7 +77,7 @@ static int have_something_to_read(int timeout)
     return 0;
 }
 
-static int read_command_from_device(void)
+static void read_command_from_device(void)
 {
     StreamDevHeader hdr;
     uint8_t msg[64];
@@ -86,40 +86,32 @@ static int read_command_from_device(void)
     std::lock_guard<std::mutex> stream_guard(stream_mtx);
     n = read(streamfd, &hdr, sizeof(hdr));
     if (n != sizeof(hdr)) {
-        syslog(LOG_WARNING,
-               "read command from device FAILED -- read %d expected %lu\n",
-               n, sizeof(hdr));
-        return -1;
+        throw std::runtime_error("read command from device FAILED -- read " + std::to_string(n) +
+                                 " expected " + std::to_string(sizeof(hdr)));
     }
     if (hdr.protocol_version != STREAM_DEVICE_PROTOCOL) {
-        syslog(LOG_WARNING, "BAD VERSION %d (expected is %d)\n", hdr.protocol_version,
-               STREAM_DEVICE_PROTOCOL);
-        return -1;
+        throw std::runtime_error("BAD VERSION " + std::to_string(hdr.protocol_version) +
+                                 " (expected is " + std::to_string(STREAM_DEVICE_PROTOCOL) + ")");
     }
     if (hdr.type != STREAM_TYPE_START_STOP) {
-        syslog(LOG_WARNING, "UNKNOWN msg of type %d\n", hdr.type);
-        return -1;
+        throw std::runtime_error("UNKNOWN msg of type " + std::to_string(hdr.type));
     }
     if (hdr.size >= sizeof(msg)) {
-        syslog(LOG_WARNING,
-               "msg size (%d) is too long (longer than %lu)\n",
-               hdr.size, sizeof(msg));
-        return -1;
+        throw std::runtime_error("msg size (" + std::to_string(hdr.size) + ") is too long "
+                                 "(longer than " + std::to_string(sizeof(msg)) + ")");
     }
     n = read(streamfd, &msg, hdr.size);
     if (n != hdr.size) {
-        syslog(LOG_WARNING,
-               "read command from device FAILED -- read %d expected %d\n",
-               n, hdr.size);
-        return -1;
+        throw std::runtime_error("read command from device FAILED -- read " + std::to_string(n) +
+                                 " expected " + std::to_string(hdr.size));
     }
     streaming_requested = (msg[0] != 0); /* num_codecs */
     syslog(LOG_INFO, "GOT START_STOP message -- request to %s streaming\n",
            streaming_requested ? "START" : "STOP");
     client_codecs.clear();
-    for (int i = 1; i <= msg[0]; ++i)
+    for (int i = 1; i <= msg[0]; ++i) {
         client_codecs.insert((SpiceVideoCodecType) msg[i]);
-    return 1;
+    }
 }
 
 static int read_command(bool blocking)
@@ -133,7 +125,8 @@ static int read_command(bool blocking)
             sleep(1);
             continue;
         }
-        return read_command_from_device();
+        read_command_from_device();
+        break;
     }
 
     return 1;
-- 
2.14.3