#include "safeio.h"
#include <sys/uio.h>

const SafeIOError exception_SafeIOError;
const SafeIOEOF   exception_SafeIOEOF  ;

void read_safe(int fd,void *buf,size_t size) {
  assert(size>0);
  while (size>0) {
    const ssize_t got(read(fd,buf,size));
    assert(got>=-1);
    if (got<=0) {
      warning("read_safe: fd=%d size=%zu: %s",fd,size,(got==0?"EOF":strerror(errno)));
      // Do not throw ?exc1:exc2 as it would get upcasted.
      if (got==0||(got==-1&&errno==ECONNRESET))
	throw exception_SafeIOEOF;
      throw exception_SafeIOError;
    }
    assert(size_t(got)<=size);
    buf=static_cast<uint8_t *>(buf)+got;
    size-=got;
  }
}

void read_safe(FILE *f,void *buf,size_t size) {
  assert(size>0);
  assert(!ferror(f));
  assert(!feof(f));
  const size_t got(fread(buf,1/*size*/,size/*nmemb*/,f));
  if (ferror(f)||feof(f)) {
    warning("read_safe: fd=%d size=%zu: %s",fileno(f),size,(ferror(f)?"error":"EOF"));
    // Do not throw ?exc1:exc2 as it would get upcasted.
    if (ferror(f))
      throw exception_SafeIOError;
    throw exception_SafeIOEOF;
  }
  // return [...] which is less than nitems only if a read error or end-of-file is encountered.
  if (size_t(got)!=size) {
    warning("read_safe: fd=%d size=%zu got=%zu",fileno(f),size,got);
    throw exception_SafeIOError;
  }
}

void write_safe(int fd,const void *buf,size_t size) {
  assert(size>0);
  const ssize_t got(write(fd,buf,size));
  if (got==-1) {
    warning("Error writing %zu to fd %d: %m",size,fd);
    throw exception_SafeIOError;
  }
  assert(got>0);
  if (size_t(got)!=size) {
    warning("Wrote only %zd of %zu to fd %d",got,size,fd);
    throw exception_SafeIOEOF;
  }
}

void write_safe(FILE *f,const void *buf,size_t size) {
  assert(size>0);
  assert(!ferror(f));
  const size_t got(fwrite(buf,1/*size*/,size/*nmemb*/,f));
  if (ferror(f)) {
    warning("Error writing %zu to FILE * of fd %d",size,fileno(f));
    throw exception_SafeIOError;
  }
  if (got!=size) {
    warning("Wrote only %zu of %zu to FILE * of fd %d",got,size,fileno(f));
    throw exception_SafeIOEOF;
  }
}

void writev_safe_(int fd,const struct iovec *iov, int iovcnt) {
  size_t size=0;
  for (int ix=0;ix<iovcnt;++ix)
    size+=iov[ix].iov_len;
  assert(size>0);
  const ssize_t got(writev(fd,iov,iovcnt));
  if (got==-1) {
    warning("Error writing %zu iovec to fd %d: %m",size,fd);
    throw exception_SafeIOError;
  }
  assert(got>0);
  if (size_t(got)!=size) {
    warning("Wrote only %zd of %zu iovec to fd %d",got,size,fd);
    throw exception_SafeIOEOF;
  }
}