[Spice-devel] [PATCH 11/17] Move read, write and locking into the 'Stream' class
Christophe de Dinechin
cdupontd at redhat.com
Wed Feb 21 09:08:21 UTC 2018
> On 20 Feb 2018, at 22:24, Jonathon Jongsma <jjongsma at redhat.com> wrote:
>
> On Tue, 2018-02-20 at 14:29 +0100, Lukáš Hrázký wrote:
>> On Tue, 2018-02-20 at 10:47 +0100, Christophe de Dinechin wrote:
>>>> On 20 Feb 2018, at 10:43, Lukáš Hrázký <lhrazky at redhat.com>
>>>> wrote:
>>>>
>>>> On Fri, 2018-02-16 at 17:15 +0100, Christophe de Dinechin wrote:
>>>>> From: Christophe de Dinechin <dinechin at redhat.com>
>>>>>
>>>>> Signed-off-by: Christophe de Dinechin <dinechin at redhat.com>
>>>>> ---
>>>>> src/spice-streaming-agent.cpp | 86 +++++++++++++++++++++++-----
>>>>> ---------------
>>>>> 1 file changed, 47 insertions(+), 39 deletions(-)
>>>>>
>>>>> diff --git a/src/spice-streaming-agent.cpp b/src/spice-
>>>>> streaming-agent.cpp
>>>>> index f0d79ae..a989ee7 100644
>>>>> --- a/src/spice-streaming-agent.cpp
>>>>> +++ b/src/spice-streaming-agent.cpp
>>>>> @@ -71,18 +71,30 @@ class Stream
>>>>> public:
>>>>> Stream(const char *name)
>>>>
>>>> I would like to name the class something more descriptive for
>>>> what it
>>>> is becoming. Class named Stream in a file named
>>>> "stream.{cpp,hpp}"
>>>> could be almost anything.
>>>
>>> But it’s not named “Stream”, it’s called
>>> “spice::streaming_agent::Stream” ;-)
>>>
>>> I chose short names because I was in that namespace. Otherwise, I
>>> agree with you.
>>>
>>> Do you think that the name is still too vague even within the
>>> namespace?
>>
>> I think so. Everything in streaming agent is in that namespace, even
>> if
>> it wasn't, you know you're looking at the streaming agent code and
>> think of the types in that context. Stream is still a pretty generic
>> name, I suppose you could imagine a number of things under it.
>>
>> So what is this class in our case. It handles the socket
>> communication
>> over the streaming channel to the server. Is it accurate to call it a
>> channel here? If so, maybe StreamingChannel?
>
> It's true that "Stream" in the context of the streaming agent could
> make you think that it was actually representing the encoded video
> stream, rather than an encapsulation of a communication channel. But I
> don't like the name StreamDispatcher. Glib uses the name GIOChannel for
> something similar. Maybe IOChannel?
I like the fact that IOChannel points out that it’s both input and output. Sounds good to me.
>
>>
>>>> My best name is StreamDispatcher so far, not
>>>> entirely happy about it :)
>>>
>>>
>>>>
>>>>> {
>>>>> - fd = open(name, O_RDWR);
>>>>> - if (fd < 0)
>>>>> + streamfd = open(name, O_RDWR);
>>>>> + if (streamfd < 0)
>>>>> throw std::runtime_error("failed to open streaming
>>>>> device");
>>>>> }
>>>>> ~Stream()
>>>>> {
>>>>> - close(fd);
>>>>> + close(streamfd);
>>>>> }
>>>>> - operator int() { return fd; }
>>>>> + operator int() { return streamfd; }
>>>>> +
>>>>> + int have_something_to_read(int timeout);
>>>>> + int read_command_from_device(void);
>>>>> + int read_command(bool blocking);
>>>>> +
>>>>> + size_t write_all(const void *buf, const size_t len);
>>>>
>>>> This method could also use a better name. write_bytes()?
>>>> write_buffer()?
>>>
>>> I intended to do a rename in a follow up. My current choice was
>>> “write_packet”, because precisely, it’s not writing bytes or a
>>> buffer, it’s making sure the whole packet gets sent.
>>
>> What do you mean by packet here? Does it have a specific meaning in
>> this context? It just sends an array of binary data, doesn't it? Like
>> later on you use it to write the header and message body separately.
>>
>>>>
>>>>> + int send_format(unsigned w, unsigned h, uint8_t c);
>>>>> + int send_frame(const void *buf, const unsigned size);
>>>>> + void send_cursor(uint16_t width, uint16_t height,
>>>>> + uint16_t hotspot_x, uint16_t hotspot_y,
>>>>> + std::function<void(uint32_t *)>
>>>>> fill_cursor);
>>>>>
>>>>> private:
>>>>> - int fd = -1;
>>>>> + int streamfd = -1;
>>>>> + std::mutex mutex;
>>>>> };
>>>>>
>>>>> }} // namespace spice::streaming_agent
>>>>> @@ -92,9 +104,8 @@ static bool streaming_requested = false;
>>>>> static bool quit_requested = false;
>>>>> static bool log_binary = false;
>>>>> static std::set<SpiceVideoCodecType> client_codecs;
>>>>> -static std::mutex stream_mtx;
>>>>>
>>>>> -static int have_something_to_read(int streamfd, int timeout)
>>>>> +int Stream::have_something_to_read(int timeout)
>>>>> {
>>>>> struct pollfd pollfd = {streamfd, POLLIN, 0};
>>>>>
>>>>> @@ -110,13 +121,13 @@ static int have_something_to_read(int
>>>>> streamfd, int timeout)
>>>>> return 0;
>>>>> }
>>>>>
>>>>> -static int read_command_from_device(int streamfd)
>>>>> +int Stream::read_command_from_device()
>>>>> {
>>>>> StreamDevHeader hdr;
>>>>> uint8_t msg[64];
>>>>> int n;
>>>>>
>>>>> - std::lock_guard<std::mutex> stream_guard(stream_mtx);
>>>>> + std::lock_guard<std::mutex> stream_guard(mutex);
>>>>> n = read(streamfd, &hdr, sizeof(hdr));
>>>>> if (n != sizeof(hdr)) {
>>>>> syslog(LOG_WARNING,
>>>>> @@ -155,29 +166,28 @@ static int read_command_from_device(int
>>>>> streamfd)
>>>>> return 1;
>>>>> }
>>>>>
>>>>> -static int read_command(int streamfd, bool blocking)
>>>>> +int Stream::read_command(bool blocking)
>>>>> {
>>>>> int timeout = blocking?-1:0;
>>>>> while (!quit_requested) {
>>>>> - if (!have_something_to_read(streamfd, timeout)) {
>>>>> + if (!have_something_to_read(timeout)) {
>>>>> if (!blocking) {
>>>>> return 0;
>>>>> }
>>>>> sleep(1);
>>>>> continue;
>>>>> }
>>>>> - return read_command_from_device(streamfd);
>>>>> + return read_command_from_device();
>>>>> }
>>>>>
>>>>> return 1;
>>>>> }
>>>>>
>>>>> -static size_t
>>>>> -write_all(int fd, const void *buf, const size_t len)
>>>>> +size_t Stream::write_all(const void *buf, const size_t len)
>>>>> {
>>>>> size_t written = 0;
>>>>> while (written < len) {
>>>>> - int l = write(fd, (const char *) buf + written, len -
>>>>> written);
>>>>> + int l = write(streamfd, (const char *) buf + written,
>>>>> len - written);
>>>>> if (l < 0) {
>>>>> if (errno == EINTR) {
>>>>> continue;
>>>>> @@ -191,7 +201,7 @@ write_all(int fd, const void *buf, const
>>>>> size_t len)
>>>>> return written;
>>>>> }
>>>>>
>>>>> -static int spice_stream_send_format(int streamfd, unsigned w,
>>>>> unsigned h, uint8_t c)
>>>>> +int Stream::send_format(unsigned w, unsigned h, uint8_t c)
>>>>> {
>>>>> const size_t msgsize = sizeof(FormatMessage);
>>>>> const size_t hdrsize = sizeof(StreamDevHeader);
>>>>> @@ -210,14 +220,14 @@ static int spice_stream_send_format(int
>>>>> streamfd, unsigned w, unsigned h, uint8_
>>>>> }
>>>>> };
>>>>> syslog(LOG_DEBUG, "writing format\n");
>>>>> - std::lock_guard<std::mutex> stream_guard(stream_mtx);
>>>>> - if (write_all(streamfd, &msg, msgsize) != msgsize) {
>>>>> + std::lock_guard<std::mutex> stream_guard(mutex);
>>>>> + if (write_all(&msg, msgsize) != msgsize) {
>>>>> return EXIT_FAILURE;
>>>>> }
>>>>> return EXIT_SUCCESS;
>>>>> }
>>>>>
>>>>> -static int spice_stream_send_frame(int streamfd, const void
>>>>> *buf, const unsigned size)
>>>>> +int Stream::send_frame(const void *buf, const unsigned size)
>>>>> {
>>>>> ssize_t n;
>>>>> const size_t msgsize = sizeof(FormatMessage);
>>>>> @@ -231,8 +241,8 @@ static int spice_stream_send_frame(int
>>>>> streamfd, const void *buf, const unsigned
>>>>> .msg = {}
>>>>> };
>>>>>
>>>>> - std::lock_guard<std::mutex> stream_guard(stream_mtx);
>>>>> - n = write_all(streamfd, &msg, msgsize);
>>>>> + std::lock_guard<std::mutex> stream_guard(mutex);
>>>>> + n = write_all(&msg, msgsize);
>>>>> syslog(LOG_DEBUG,
>>>>> "wrote %ld bytes of header of data msg with frame of
>>>>> size %u bytes\n",
>>>>> n, msg.hdr.size);
>>>>> @@ -241,7 +251,7 @@ static int spice_stream_send_frame(int
>>>>> streamfd, const void *buf, const unsigned
>>>>> n, msgsize);
>>>>> return EXIT_FAILURE;
>>>>> }
>>>>> - n = write_all(streamfd, buf, size);
>>>>> + n = write_all(buf, size);
>>>>> syslog(LOG_DEBUG, "wrote data msg body of size %ld\n", n);
>>>>> if (n != size) {
>>>>> syslog(LOG_WARNING, "write_all header: wrote %ld
>>>>> expected %u\n",
>>>>> @@ -294,11 +304,10 @@ static void usage(const char *progname)
>>>>> exit(1);
>>>>> }
>>>>>
>>>>> -static void
>>>>> -send_cursor(int streamfd,
>>>>> - uint16_t width, uint16_t height,
>>>>> - uint16_t hotspot_x, uint16_t hotspot_y,
>>>>> - std::function<void(uint32_t *)> fill_cursor)
>>>>> +void
>>>>> +Stream::send_cursor(uint16_t width, uint16_t height,
>>>>> + uint16_t hotspot_x, uint16_t hotspot_y,
>>>>> + std::function<void(uint32_t *)>
>>>>> fill_cursor)
>>>>> {
>>>>> if (width >= STREAM_MSG_CURSOR_SET_MAX_WIDTH ||
>>>>> height >= STREAM_MSG_CURSOR_SET_MAX_HEIGHT)
>>>>> @@ -332,11 +341,11 @@ send_cursor(int streamfd,
>>>>> uint32_t *pixels = reinterpret_cast<uint32_t *>(cursor_msg-
>>>>>> msg.data);
>>>>> fill_cursor(pixels);
>>>>>
>>>>> - std::lock_guard<std::mutex> stream_guard(stream_mtx);
>>>>> - write_all(streamfd, storage.get(), cursor_msgsize);
>>>>> + std::lock_guard<std::mutex> stream_guard(mutex);
>>>>> + write_all(storage.get(), cursor_msgsize);
>>>>> }
>>>>>
>>>>> -static void cursor_changes(int streamfd, Display *display, int
>>>>> event_base)
>>>>> +static void cursor_changes(Stream *stream, Display *display,
>>>>> int event_base)
>>>>> {
>>>>> unsigned long last_serial = 0;
>>>>>
>>>>> @@ -358,18 +367,18 @@ static void cursor_changes(int streamfd,
>>>>> Display *display, int event_base)
>>>>> for (unsigned i = 0; i < cursor->width * cursor-
>>>>>> height; ++i)
>>>>> pixels[i] = cursor->pixels[i];
>>>>> };
>>>>> - send_cursor(streamfd,
>>>>> - cursor->width, cursor->height, cursor-
>>>>>> xhot, cursor->yhot, fill_cursor);
>>>>> + stream->send_cursor(cursor->width, cursor->height,
>>>>> + cursor->xhot, cursor->yhot,
>>>>> fill_cursor);
>>>>> }
>>>>> }
>>>>>
>>>>> static void
>>>>> -do_capture(int streamfd, const char *streamport, FILE *f_log)
>>>>> +do_capture(Stream &stream, const char *streamport, FILE
>>>>> *f_log)
>>>>> {
>>>>> unsigned int frame_count = 0;
>>>>> while (!quit_requested) {
>>>>> while (!quit_requested && !streaming_requested) {
>>>>> - if (read_command(streamfd, true) < 0) {
>>>>> + if (stream.read_command(true) < 0) {
>>>>> syslog(LOG_ERR, "FAILED to read command\n");
>>>>> return;
>>>>> }
>>>>> @@ -413,7 +422,7 @@ do_capture(int streamfd, const char
>>>>> *streamport, FILE *f_log)
>>>>>
>>>>> syslog(LOG_DEBUG, "wXh %uX%u codec=%u\n",
>>>>> width, height, codec);
>>>>>
>>>>> - if (spice_stream_send_format(streamfd, width,
>>>>> height, codec) == EXIT_FAILURE)
>>>>> + if (stream.send_format(width, height, codec)
>>>>> == EXIT_FAILURE)
>>>>> throw std::runtime_error("FAILED to send
>>>>> format message");
>>>>> }
>>>>> if (f_log) {
>>>>> @@ -425,13 +434,12 @@ do_capture(int streamfd, const char
>>>>> *streamport, FILE *f_log)
>>>>> hexdump(frame.buffer, frame.buffer_size,
>>>>> f_log);
>>>>> }
>>>>> }
>>>>> - if (spice_stream_send_frame(streamfd,
>>>>> - frame.buffer,
>>>>> frame.buffer_size) == EXIT_FAILURE) {
>>>>> + if (stream.send_frame(frame.buffer,
>>>>> frame.buffer_size) == EXIT_FAILURE) {
>>>>> syslog(LOG_ERR, "FAILED to send a frame\n");
>>>>> break;
>>>>> }
>>>>> //usleep(1);
>>>>> - if (read_command(streamfd, false) < 0) {
>>>>> + if (stream.read_command(false) < 0) {
>>>>> syslog(LOG_ERR, "FAILED to read command\n");
>>>>> return;
>>>>> }
>>>>> @@ -520,7 +528,7 @@ int main(int argc, char* argv[])
>>>>> XFixesSelectCursorInput(display, rootwindow,
>>>>> XFixesDisplayCursorNotifyMask);
>>>>>
>>>>> Stream streamfd(streamport);
>>>>> - std::thread cursor_th(cursor_changes, (int) streamfd,
>>>>> display, event_base);
>>>>> + std::thread cursor_th(cursor_changes, &streamfd, display,
>>>>> event_base);
>>>>> cursor_th.detach();
>>>>>
>>>>> int ret = EXIT_SUCCESS;
>>>
>>>
>>
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