miller/c/stream/stream.c
2017-02-14 22:06:39 -05:00

248 lines
9 KiB
C

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "lib/mlrutil.h"
#include "lib/mlr_globals.h"
#include "containers/lrec.h"
#include "containers/sllv.h"
#include "input/lrec_readers.h"
#include "mapping/mappers.h"
#include "output/lrec_writers.h"
static int do_stream_chained_in_place(context_t* pctx, cli_opts_t* popts);
static int do_stream_chained_to_stdout(context_t* pctx, sllv_t* pmapper_list, cli_opts_t* popts);
static int do_file_chained(char* filename, context_t* pctx,
lrec_reader_t* plrec_reader, sllv_t* pmapper_list, lrec_writer_t* plrec_writer, FILE* output_stream,
cli_opts_t* popts);
static sllv_t* chain_map(lrec_t* pinrec, context_t* pctx, sllve_t* pmapper_list_head);
static void drive_lrec(lrec_t* pinrec, context_t* pctx, sllve_t* pmapper_list_head, lrec_writer_t* plrec_writer,
FILE* output_stream);
typedef void progress_indicator_t(context_t* pctx, long long nr_progress_mod);
static void null_progress_indicator(context_t* pctx, long long nr_progress_mod);
static void stderr_progress_indicator(context_t* pctx, long long nr_progress_mod);
// ----------------------------------------------------------------
int do_stream_chained(context_t* pctx, sllv_t* pmapper_list, cli_opts_t* popts) {
if (popts->do_in_place) {
return do_stream_chained_in_place(pctx, popts);
} else {
return do_stream_chained_to_stdout(pctx, pmapper_list, popts);
}
}
// ----------------------------------------------------------------
// For in-place mode, reconstruct the mappers on each input file. E.g. 'mlr -I head -n 2
// foo bar' should do head -n 2 on foo as well as on bar.
//
// I could have implemented this with a single construction of the mappers and having each
// mapper implement a virtual reset() method. However, having effectively two initalizers
// per mapper -- constructor and reset method -- I'd surely miss some logic somewhere.
// With in-place mode being a less frequently used code path, this would likely lead to
// latent bugs. So while it seems inelegant to re-parse part of the command line over and
// over again to reconstruct mappers for each file, this approach leads to greater code
// stability.
static int do_stream_chained_in_place(context_t* pctx, cli_opts_t* popts) {
MLR_INTERNAL_CODING_ERROR_IF(popts->filenames == NULL);
MLR_INTERNAL_CODING_ERROR_IF(popts->filenames->length == 0);
int ok = 1;
// Read from each file name in turn
for (sllse_t* pe = popts->filenames->phead; pe != NULL; pe = pe->pnext) {
// Allocate reader, mappers, and writer individually for each file name.
// This way CSV headers appear in each file, head -n 10 puts 10 rows for
// each output file, and so on.
lrec_reader_t* plrec_reader = lrec_reader_alloc_or_die(&popts->reader_opts);
lrec_writer_t* plrec_writer = lrec_writer_alloc_or_die(&popts->writer_opts);
int argi = popts->mapper_argb;
int unused;
sllv_t* pmapper_list = cli_parse_mappers(popts->argv, &argi, popts->argc, popts, &unused);
MLR_INTERNAL_CODING_ERROR_IF(pmapper_list->length < 1); // Should not have been allowed by the CLI parser.
char* filename = pe->value;
char* tempname = alloc_suffixed_temp_file_name(filename);
FILE* output_stream = fopen(tempname, "wb");
if (output_stream == NULL) {
perror("fopen");
fprintf(stderr, "%s: Could not open \"%s\" for write.\n",
MLR_GLOBALS.bargv0, tempname);
exit(1);
}
pctx->filenum++;
pctx->filename = filename;
pctx->fnr = 0;
ok = do_file_chained(filename, pctx, plrec_reader, pmapper_list, plrec_writer,
output_stream, popts) && ok;
// For in-place mode, there's no breaking from the loop over input files. Just an early
// return from the mapper chain, which has already just happened.
if (pctx->force_eof == TRUE) // e.g. mlr head
pctx->force_eof = FALSE;
// Mappers and writers receive end-of-stream notifications via null input record.
// Do that, now that data from the input file have been exhausted.
drive_lrec(NULL, pctx, pmapper_list->phead, plrec_writer, output_stream);
// Drain the pretty-printer.
plrec_writer->pprocess_func(plrec_writer->pvstate, output_stream, NULL, pctx);
fclose(output_stream);
int rc = rename(tempname, filename);
if (rc != 0) {
perror("rename");
fprintf(stderr, "%s: Could not rename \"%s\" to \"%s\".\n",
MLR_GLOBALS.bargv0, tempname, filename);
exit(1);
}
free(tempname);
plrec_reader->pfree_func(plrec_reader);
plrec_writer->pfree_func(plrec_writer, pctx);
mapper_chain_free(pmapper_list, pctx);
}
return ok;
}
// ----------------------------------------------------------------
static int do_stream_chained_to_stdout(context_t* pctx, sllv_t* pmapper_list, cli_opts_t* popts) {
FILE* output_stream = stdout;
lrec_reader_t* plrec_reader = lrec_reader_alloc_or_die(&popts->reader_opts);
lrec_writer_t* plrec_writer = lrec_writer_alloc_or_die(&popts->writer_opts);
MLR_INTERNAL_CODING_ERROR_IF(pmapper_list->length < 1); // Should not have been allowed by the CLI parser.
int ok = 1;
if (popts->filenames == NULL) {
// No input at all
} else if (popts->filenames->length == 0) {
// Zero file names means read from standard input
pctx->filenum++;
pctx->filename = "(stdin)";
pctx->fnr = 0;
ok = do_file_chained("-", pctx, plrec_reader, pmapper_list, plrec_writer,
output_stream, popts) && ok;
} else {
// Read from each file name in turn
for (sllse_t* pe = popts->filenames->phead; pe != NULL; pe = pe->pnext) {
char* filename = pe->value;
pctx->filenum++;
pctx->filename = filename;
pctx->fnr = 0;
ok = do_file_chained(filename, pctx, plrec_reader, pmapper_list, plrec_writer,
output_stream, popts) && ok;
if (pctx->force_eof == TRUE) // e.g. mlr head
break;
}
}
// Mappers and writers receive end-of-stream notifications via null input record.
// Do that, now that data from all input file(s) have been exhausted.
drive_lrec(NULL, pctx, pmapper_list->phead, plrec_writer, output_stream);
// Drain the pretty-printer.
plrec_writer->pprocess_func(plrec_writer->pvstate, output_stream, NULL, pctx);
plrec_reader->pfree_func(plrec_reader);
plrec_writer->pfree_func(plrec_writer, pctx);
return ok;
}
// ----------------------------------------------------------------
static int do_file_chained(char* filename, context_t* pctx,
lrec_reader_t* plrec_reader, sllv_t* pmapper_list, lrec_writer_t* plrec_writer, FILE* output_stream,
cli_opts_t* popts)
{
void* pvhandle = plrec_reader->popen_func(plrec_reader->pvstate, popts->reader_opts.prepipe, filename);
progress_indicator_t* pindicator = popts->nr_progress_mod == 0LL
? null_progress_indicator
: stderr_progress_indicator;
// Start-of-file hook, e.g. expecting CSV headers on input.
plrec_reader->psof_func(plrec_reader->pvstate, pvhandle);
while (1) {
lrec_t* pinrec = plrec_reader->pprocess_func(plrec_reader->pvstate, pvhandle, pctx);
if (pinrec == NULL)
break;
if (pctx->force_eof == TRUE) { // e.g. mlr head
lrec_free(pinrec);
break;
}
pctx->nr++;
pctx->fnr++;
pindicator(pctx, popts->nr_progress_mod);
drive_lrec(pinrec, pctx, pmapper_list->phead, plrec_writer, output_stream);
}
plrec_reader->pclose_func(plrec_reader->pvstate, pvhandle, popts->reader_opts.prepipe);
return 1;
}
// ----------------------------------------------------------------
static void drive_lrec(lrec_t* pinrec, context_t* pctx, sllve_t* pmapper_list_head, lrec_writer_t* plrec_writer,
FILE* output_stream)
{
sllv_t* outrecs = chain_map(pinrec, pctx, pmapper_list_head);
if (outrecs != NULL) {
for (sllve_t* pe = outrecs->phead; pe != NULL; pe = pe->pnext) {
lrec_t* poutrec = pe->pvvalue;
if (poutrec != NULL) // writer frees records (sllv void-star payload)
plrec_writer->pprocess_func(plrec_writer->pvstate, output_stream, poutrec, pctx);
}
sllv_free(outrecs); // we free the list
}
}
// ----------------------------------------------------------------
// Map a single input record (maybe null at end of input stream) to zero or
// more output records.
//
// Return: list of lrec_t*. Input: lrec_t* and list of mapper_t*.
static sllv_t* chain_map(lrec_t* pinrec, context_t* pctx, sllve_t* pmapper_list_head) {
mapper_t* pmapper = pmapper_list_head->pvvalue;
sllv_t* outrecs = pmapper->pprocess_func(pinrec, pctx, pmapper->pvstate);
if (pmapper_list_head->pnext == NULL) {
return outrecs;
} else if (outrecs == NULL) { // end of input stream
return NULL;
} else {
sllv_t* nextrecs = sllv_alloc();
for (sllve_t* pe = outrecs->phead; pe != NULL; pe = pe->pnext) {
lrec_t* poutrec = pe->pvvalue;
sllv_t* nextrecsi = chain_map(poutrec, pctx, pmapper_list_head->pnext);
sllv_transfer(nextrecs, nextrecsi);
sllv_free(nextrecsi);
}
sllv_free(outrecs);
return nextrecs;
}
}
// ----------------------------------------------------------------
static void stderr_progress_indicator(context_t* pctx, long long nr_progress_mod) {
long long remainder = pctx->nr % nr_progress_mod;
if (remainder == 0) {
fprintf(stderr, "NR=%lld FNR=%lld FILENAME=%s\n", pctx->nr, pctx->fnr, pctx->filename);
}
}
static void null_progress_indicator(context_t* pctx, long long nr_progress_mod) {
}