[Spice-devel] [PATCH spice-streaming-agent 5/9] Unify the structure of write_all() and read_all()

[Frediano Ziglio]

> 
> On Wed, 2018-05-16 at 05:31 -0400, Frediano Ziglio wrote:
> > > 
> > > On Tue, 2018-05-15 at 16:44 -0400, Frediano Ziglio wrote:
> > > > A bit more comment would be good. For instance why not unifying the
> > > > other
> > > > way
> > > > around?
> > > 
> > > Well, the reason is this one seems a bit cleaner and easier to read.
> > > Want me to put that in the commit message? :) Anything else? I don't
> > > feel this needs much explaining...
> > > 
> > 
> > What "seems" to you is not objective by definition.
> > In my experience I saw both implementation, they are both fine and correct
> > and different people have different styles.
> > Commit messages are not just for review now, think in 5 years possible
> > new people looking at the code.
> 
> Indeed, it is my subjective reason to pick one of the ways. That's why
> I asked you if I really should put that in the commit message.
> 
> There is nothing more to it, I just picked one way and I think we agree
> it's better to have the functions unified.
> 
> So, what do you want me to do? :)
> 

Just report this in the commit message, could be something along

"Both versions are fine but just for coherency syntax is unified.

The line

  write(fd, (const char *) buf + written, len - written);

looks over complicated to the read_all version seems more clear."

(if this is the reason why one looks more clear).

> > > > > 
> > > > > Signed-off-by: Lukáš Hrázký <lhrazky at redhat.com>
> > > > > ---
> > > > >  src/stream-port.cpp | 20 +++++++++++---------
> > > > >  src/stream-port.hpp |  4 ++--
> > > > >  2 files changed, 13 insertions(+), 11 deletions(-)
> > > > > 
> > > > > diff --git a/src/stream-port.cpp b/src/stream-port.cpp
> > > > > index 526c564..cee63ac 100644
> > > > > --- a/src/stream-port.cpp
> > > > > +++ b/src/stream-port.cpp
> > > > > @@ -17,10 +17,10 @@
> > > > >  namespace spice {
> > > > >  namespace streaming_agent {
> > > > >  
> > > > > -void read_all(int fd, void *msg, size_t len)
> > > > > +void read_all(int fd, void *buf, size_t len)
> > > > >  {
> > > > >      while (len > 0) {
> > > > > -        ssize_t n = read(fd, msg, len);
> > > > > +        ssize_t n = read(fd, buf, len);
> > > > >  
> > > > >          if (n < 0) {
> > > > >              if (errno == EINTR) {
> > > > > @@ -30,22 +30,24 @@ void read_all(int fd, void *msg, size_t len)
> > > > >          }
> > > > >  
> > > > >          len -= n;
> > > > > -        msg = (uint8_t *) msg + n;
> > > > > +        buf = (uint8_t *) buf + n;
> > > > >      }
> > > > >  }
> > > > >  
> > > > > -void write_all(int fd, const void *buf, const size_t len)
> > > > > +void write_all(int fd, const void *buf, size_t len)
> > > > >  {
> > > > > -    size_t written = 0;
> > > > > -    while (written < len) {
> > > > > -        int l = write(fd, (const char *) buf + written, len -
> > > > > written);
> > > > > -        if (l < 0) {
> > > > > +    while (len > 0) {
> > > > > +        ssize_t n = write(fd, buf, len);
> > > > > +
> > > > > +        if (n < 0) {
> > > > >              if (errno == EINTR) {
> > > > >                  continue;
> > > > >              }
> > > > >              throw WriteError("Writing message to device failed",
> > > > >              errno);
> > > > >          }
> > > > > -        written += l;
> > > > > +
> > > > > +        len -= n;
> > > > > +        buf = (uint8_t *) buf + n;

I would add a const here.

> > > > >      }
> > > > >  }
> > > > >  
> > > > > diff --git a/src/stream-port.hpp b/src/stream-port.hpp
> > > > > index 7780a37..b2d8352 100644
> > > > > --- a/src/stream-port.hpp
> > > > > +++ b/src/stream-port.hpp
> > > > > @@ -13,8 +13,8 @@
> > > > >  namespace spice {
> > > > >  namespace streaming_agent {
> > > > >  
> > > > > -void read_all(int fd, void *msg, size_t len);
> > > > > -void write_all(int fd, const void *buf, const size_t len);
> > > > > +void read_all(int fd, void *buf, size_t len);
> > > > > +void write_all(int fd, const void *buf, size_t len);
> > > > >  
> > > > >  }} // namespace spice::streaming_agent
> > > > >  
> > > > 
> > > > Frediano
>