/** * Does a non-blocking read and either reads in the amount you requested * with "need" or less so you can try again. It sets out_len to what is * available (<= need) so you can decide after that. You can keep attempting * to read more and more (up to buf->len) and you'll get the same start point * each time. * * Once you're done with the data you've been trying to read, you use IOBuf_read_commit * to commit the "need" amount and then start doing new reads. * * Internally this works like a "half open ring buffer" and it tries to greedily * read as much as possible without blocking or copying. * * To just get as much as possible, use the IOBuf_read_some macro. */ char *IOBuf_read(IOBuf *buf, int need, int *out_len) { int rc = 0; assert(buf->cur + buf->avail <= buf->len && "Buffer math off, cur+avail can't be more than > len."); assert(buf->cur >= 0 && "Buffer cur can't be < 0"); assert(buf->avail >= 0 && "Buffer avail can't be < 0"); assert(need <= buf->len && "Request for more than possible in the buffer."); if(IOBuf_closed(buf)) { if(buf->avail > 0) { *out_len = buf->avail; } else { *out_len = 0; return NULL; } } else if(buf->avail < need) { if(buf->cur > 0 && IOBuf_compact_needed(buf, need)) { IOBuf_compact(buf); } rc = buf->recv(buf, IOBuf_read_point(buf), IOBuf_remaining(buf)); if(rc <= 0) { debug("Socket was closed, will return only what's available: %d", buf->avail); buf->closed = 1; } else { buf->avail = buf->avail + rc; } if(buf->avail < need) { // less than expected *out_len = buf->avail; } else { // more than expected *out_len = need; } } else if(buf->avail >= need) { *out_len = need; } else { sentinel("Invalid branch processing buffer, Tell Zed."); } return IOBuf_start(buf); error: return NULL; }
char *test_IOBuf_read_operations() { char *data = NULL; int avail = 0; Connection *conn = fake_conn("/dev/zero", O_RDONLY); mu_assert(conn != NULL, "Failed to make fake /dev/zero connection."); IOBuf *buf = conn->iob; IOBuf_resize(buf, 31); mu_assert(buf->len == 31, "Wrong size after resize."); data = IOBuf_start(buf); avail = IOBuf_avail(buf); mu_assert(data != NULL, "Didn't get a data response on begin."); mu_assert(data == buf->buf, "Begin on fresh iobuf should be at the beginning."); mu_assert(avail == 0, "Should not have anything available yet."); data = IOBuf_read(buf, 10, &avail); mu_assert(data != NULL, "Should get something always."); mu_assert(data == IOBuf_start(buf), "First read should work from start."); mu_assert(data == buf->buf, "First read should be at start of internal buf."); mu_assert(avail == 10, "Should get 10 bytes."); // check compacting mu_assert(!IOBuf_compact_needed(buf, 10), "Should not need compacting for 10."); mu_assert(IOBuf_compact_needed(buf, 100), "SHOULD need compacting for 100."); mu_assert(IOBuf_read_commit(buf, 10) != -1, "Failed to commit."); data = IOBuf_start(buf); avail = IOBuf_avail(buf); mu_assert(data != NULL, "Didn't get a data response on begin."); mu_assert(data != buf->buf, "Later reads should not be at the start."); mu_assert(avail == 21, "Should have 21 bytes available in the buf already."); data = IOBuf_read(buf, 10, &avail); mu_assert(data != NULL, "Should get something always."); mu_assert(avail == 10, "Should get 10 bytes."); mu_assert(IOBuf_read_commit(buf, 10) != -1, "Finaly commit failed."); data = IOBuf_start(buf); avail = IOBuf_avail(buf); mu_assert(data != NULL, "Didn't get a data response on begin."); mu_assert(data != buf->buf, "Later reads should not be at the start."); mu_assert(avail == 11, "Should have 11 bytes available in the buf already."); // now test two reads, one that fits one that doesn't then commit // remember this doesn't *return* anything, just a pointer to the start data = IOBuf_read(buf, 5, &avail); mu_assert(data != NULL, "Should get something always."); mu_assert(avail == 5, "Should get 10 bytes."); // ok we didn't want 5 we want 20, so this will cause a compact data = IOBuf_read(buf, 20, &avail); mu_assert(data != NULL, "Should get something always."); mu_assert(avail == 20, "Should get 10 bytes."); mu_assert(IOBuf_read_commit(buf, 21) != -1, "Final commit failed."); debug("We've got %d avail after the last read.", buf->avail); mu_assert(buf->avail == 10, "Should have 11 still in the queue."); data = IOBuf_read_all(buf, 30, 1); mu_assert(data != NULL, "Failed to read all."); mu_assert(buf->avail == 1, "Should have 1 in the queue."); data = IOBuf_read_some(buf, &avail); mu_assert(data != NULL, "Failed to read some."); mu_assert(buf->avail == 31, "Should be full."); mu_assert(avail == 31, "And we should get the full amount."); fake_conn_close(conn); return NULL; }