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Return a boolean from pv__transfer_read/write, where false indicates a transient error.

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This commit is contained in:
Andrew Wood
2026-04-19 21:47:46 +01:00
parent ef9240a7a5
commit 496b1e431e
1 changed files with 30 additions and 24 deletions
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src/pv/transfer.c
+30 -24
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@@ -294,7 +294,6 @@ static ssize_t pv__transfer__write_repeated(int fd, char *buf, size_t count, boo
return total_written;
}
/* TODO: make pv__transfer_read() return a boolean, for easier understanding. */
/*
* Read some data from the given file descriptor, updating the state.
@@ -329,9 +328,14 @@ static ssize_t pv__transfer__write_repeated(int fd, char *buf, size_t count, boo
* sets *eof_in to true. If all data in the buffer has been written at this
* point, then also sets *eof_out to true.
*
* Returns zero if there was a transient error, otherwise returns 1.
* Returns true if the transfer can continue normally (meaning some data was
* transferred, or there was an error or an EOF that has caused the state to
* be updated).
*
* Returns false if there was a transient error and so the transfer should
* not continue, but be retried shortly instead.
*/
static int pv__transfer_read(pvstate_t state, int fd, bool *eof_in, bool *eof_out, off_t max_to_write)
static bool pv__transfer_read(pvstate_t state, int fd, bool *eof_in, bool *eof_out, off_t max_to_write)
{
bool do_not_skip_errors;
size_t bytes_can_read;
@@ -444,7 +448,7 @@ static int pv__transfer_read(pvstate_t state, int fd, bool *eof_in, bool *eof_ou
*eof_in = true;
if (state->transfer.write_position >= state->transfer.read_position)
*eof_out = true;
return 1;
return true;
} else if (nread > 0) {
/*
* Read returned >0, so data was successfully read - clear
@@ -464,7 +468,7 @@ static int pv__transfer_read(pvstate_t state, int fd, bool *eof_in, bool *eof_ou
#endif /* HAVE_SPLICE */
/* Update the counter of all bytes read so far. */
state->transfer.total_bytes_read += nread;
return 1;
return true;
}
/*
@@ -473,12 +477,12 @@ static int pv__transfer_read(pvstate_t state, int fd, bool *eof_in, bool *eof_ou
/*
* If a read error occurred but it was EINTR or EAGAIN, wait briefly
* and return zero, since this was a transient error.
* and return false, since this was a transient error.
*/
if ((EINTR == errno) || (EAGAIN == errno)) {
debug("%s %d: %s: %s", "fd", fd, "transient error - waiting briefly", strerror(errno));
(void) is_data_ready(-1, NULL, -1, NULL, 10000);
return 0;
return false;
}
/*
@@ -499,7 +503,7 @@ static int pv__transfer_read(pvstate_t state, int fd, bool *eof_in, bool *eof_ou
if (state->transfer.write_position >= state->transfer.read_position) {
*eof_out = true;
}
return 1;
return true;
}
/*
@@ -526,7 +530,7 @@ static int pv__transfer_read(pvstate_t state, int fd, bool *eof_in, bool *eof_ou
if (state->transfer.write_position >= state->transfer.read_position) {
*eof_out = true;
}
return 1;
return true;
}
/*
@@ -627,13 +631,10 @@ static int pv__transfer_read(pvstate_t state, int fd, bool *eof_in, bool *eof_ou
}
}
return 1;
return true;
}
/* TODO: make pv__transfer_write() return a boolean, for easier understanding. */
/*
* Write state->transfer.to_write bytes of data from the transfer buffer to the output.
*
@@ -648,9 +649,14 @@ static int pv__transfer_read(pvstate_t state, int fd, bool *eof_in, bool *eof_ou
*
* If state->control.discard_input is true, does not actually write anything.
*
* Returns zero if there was a transient error, otherwise returns 1.
* Returns true if the transfer can continue normally (meaning some data was
* transferred, or there was an error or an EOF that has caused the state to
* be updated).
*
* Returns false if there was a transient error and so the transfer should
* not continue, but be retried shortly instead.
*/
static int pv__transfer_write(pvstate_t state, bool *eof_in, bool *eof_out, long *lineswritten)
static bool pv__transfer_write(pvstate_t state, bool *eof_in, bool *eof_out, long *lineswritten)
{
ssize_t nwritten;
int write_errno;
@@ -663,7 +669,7 @@ static int pv__transfer_write(pvstate_t state, bool *eof_in, bool *eof_out, long
state->status.exit_status |= PV_ERROREXIT_MEMORY;
*eof_out = true;
state->transfer.written = -1;
return 1;
return true;
}
nwritten = 0;
@@ -968,7 +974,7 @@ static int pv__transfer_write(pvstate_t state, bool *eof_in, bool *eof_out, long
*eof_out = true;
}
return 1;
return true;
}
/*
@@ -988,7 +994,7 @@ static int pv__transfer_write(pvstate_t state, bool *eof_in, bool *eof_out, long
debug("%s: %s", "transient write error - waiting briefly", strerror(write_errno));
}
(void) is_data_ready(-1, NULL, -1, NULL, 10000);
return 0;
return false;
}
/*
@@ -1001,7 +1007,7 @@ static int pv__transfer_write(pvstate_t state, bool *eof_in, bool *eof_out, long
*eof_out = true;
state->flags.pipe_closed = 1;
debug("%s", "SIGPIPE received - setting pipe_closed");
return 0;
return false;
}
/*
@@ -1014,7 +1020,7 @@ static int pv__transfer_write(pvstate_t state, bool *eof_in, bool *eof_out, long
*eof_out = true;
state->transfer.written = -1;
return 1;
return true;
}
@@ -1261,9 +1267,9 @@ ssize_t pv_transfer(pvstate_t state, int fd, bool *eof_in, bool *eof_out, off_t
* NB this can update state->transfer.written because of splice().
*/
if (ready_to_read) {
if (pv__transfer_read(state, fd, eof_in, eof_out, allowed) == 0) {
if (!pv__transfer_read(state, fd, eof_in, eof_out, allowed)) {
debug("%s %d: %s (%s=%s, %s=%s, %s=%lu)", "fd", fd,
"early return 0 - pv__transfer_read returned 0", "eof_in", eof_in ? "true" : "false",
"early return 0 - pv__transfer_read returned false", "eof_in", eof_in ? "true" : "false",
"eof_out", eof_out ? "true" : "false", "allowed", (unsigned long) allowed);
return 0;
}
@@ -1298,9 +1304,9 @@ ssize_t pv_transfer(pvstate_t state, int fd, bool *eof_in, bool *eof_out, off_t
&& (state->transfer.read_position > state->transfer.write_position)
&& (state->transfer.to_write > 0)
&& (NULL != lineswritten)) {
if (pv__transfer_write(state, eof_in, eof_out, lineswritten) == 0) {
if (!pv__transfer_write(state, eof_in, eof_out, lineswritten)) {
debug("%s %d: %s (%s=%s, %s=%s, %s=%lu)", "fd", fd,
"early return 0 - pv__transfer_write returned 0", "eof_in", eof_in ? "true" : "false",
"early return 0 - pv__transfer_write returned false", "eof_in", eof_in ? "true" : "false",
"eof_out", eof_out ? "true" : "false", "lineswritten", (unsigned long) lineswritten);
return 0;
}