avformat/fifo_test: Move into tests/fifo_muxer.c

This muxer solely exists to test the fifo muxer via a dedicated
test tool in libavformat/tests/fifo_muxer.c. It fulfills no
other role and it is only designed with this role in mind.

The latter can be seen in two facts: The muxer uses printf
for logging and it simply presumes the packets' data to contain
a FailingMuxerPacketData (a struct duplicated in fifo_test.c
and tests/fifo_muxer.c.); in particular, it presumes packets
to have data at all, but this need not be true with side-data
only packets and a segfault can easily be triggered by e.g.
encoding flac (our native encoder sends a side-data only packet
with updated extradata at the end of encoding).

This patch fixes this by moving the test muxer into the fifo
test tool, making it inaccessible via the API (and actually
removing it from libavformat.so and libavformat.a).
While this muxer was accessible via e.g. av_guess_format(),
it was not really usable for an API user as FailingMuxerPacketData
was not public. Therefore this is not considered a breaking change.

In order to continue to use the test muxer in the test tool,
the ordinary fifo muxer had to be overridden: fifo_muxer.c
includes lavf/fifo.c but with FIFO_TEST defined which makes
it support the fifo_test muxer. This is possible because
test tools are always linked statically to their respective
library.
Reviewed-by: Stefano Sabatini <stefasab@gmail.com>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavformat/Makefile

@@ -205,7 +205,6 @@ OBJS-$(CONFIG_EPAF_DEMUXER)              += epafdec.o pcm.o
 OBJS-$(CONFIG_FFMETADATA_DEMUXER)        += ffmetadec.o
 OBJS-$(CONFIG_FFMETADATA_MUXER)          += ffmetaenc.o
 OBJS-$(CONFIG_FIFO_MUXER)                += fifo.o
-OBJS-$(CONFIG_FIFO_TEST_MUXER)           += fifo_test.o
 OBJS-$(CONFIG_FILMSTRIP_DEMUXER)         += filmstripdec.o
 OBJS-$(CONFIG_FILMSTRIP_MUXER)           += filmstripenc.o rawenc.o
 OBJS-$(CONFIG_FITS_DEMUXER)              += fitsdec.o

libavformat/allformats.c

@@ -165,7 +165,6 @@ extern const FFOutputFormat ff_f4v_muxer;
 extern const FFInputFormat  ff_ffmetadata_demuxer;
 extern const FFOutputFormat ff_ffmetadata_muxer;
 extern const FFOutputFormat ff_fifo_muxer;
-extern const FFOutputFormat ff_fifo_test_muxer;
 extern const FFInputFormat  ff_filmstrip_demuxer;
 extern const FFOutputFormat ff_filmstrip_muxer;
 extern const FFInputFormat  ff_fits_demuxer;

libavformat/fifo.c

@@ -528,6 +528,13 @@ static int fifo_init(AVFormatContext *avf)
     atomic_init(&fifo->queue_duration, 0);
     fifo->last_sent_dts = AV_NOPTS_VALUE;
 
+#ifdef FIFO_TEST
+    /* This exists for the fifo_muxer test tool. */
+    if (fifo->format && !strcmp(fifo->format, "fifo_test")) {
+        extern const FFOutputFormat ff_fifo_test_muxer;
+        oformat = &ff_fifo_test_muxer.p;
+    } else
+#endif
     oformat = av_guess_format(fifo->format, avf->url, NULL);
     if (!oformat) {
         ret = AVERROR_MUXER_NOT_FOUND;

libavformat/fifo_test.c

-/*
- * FIFO test pseudo-muxer
- * Copyright (c) 2016 Jan Sebechlebsky
- *
- * This file is part of FFmpeg.
- *
- * FFmpeg is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public License
- * as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * FFmpeg is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with FFmpeg; if not, write to the Free Software * Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#include <stdlib.h>
-
-#include "libavutil/opt.h"
-#include "libavutil/time.h"
-
-#include "avformat.h"
-#include "mux.h"
-#include "url.h"
-
-/* Implementation of mock muxer to simulate real muxer failures */
-
-#define MAX_TST_PACKETS 128
-#define SLEEPTIME_50_MS 50000
-#define SLEEPTIME_10_MS 10000
-
-/* Implementation of mock muxer to simulate real muxer failures */
-
-/* This is structure of data sent in packets to
- * failing muxer */
-typedef struct FailingMuxerPacketData {
-    int ret;             /* return value of write_packet call*/
-    int recover_after;   /* set ret to zero after this number of recovery attempts */
-    unsigned sleep_time; /* sleep for this long in write_packet to simulate long I/O operation */
-} FailingMuxerPacketData;
-
-
-typedef struct FailingMuxerContext {
-    AVClass *class;
-    int write_header_ret;
-    int write_trailer_ret;
-    /* If non-zero, summary of processed packets will be printed in deinit */
-    int print_deinit_summary;
-
-    int flush_count;
-    int pts_written[MAX_TST_PACKETS];
-    int pts_written_nr;
-} FailingMuxerContext;
-
-static int failing_write_header(AVFormatContext *avf)
-{
-    FailingMuxerContext *ctx = avf->priv_data;
-    return ctx->write_header_ret;
-}
-
-static int failing_write_packet(AVFormatContext *avf, AVPacket *pkt)
-{
-    FailingMuxerContext *ctx = avf->priv_data;
-    int ret = 0;
-    if (!pkt) {
-        ctx->flush_count++;
-    } else {
-        FailingMuxerPacketData *data = (FailingMuxerPacketData*) pkt->data;
-
-        if (!data->recover_after) {
-            data->ret = 0;
-        } else {
-            data->recover_after--;
-        }
-
-        ret = data->ret;
-
-        if (data->sleep_time) {
-            int64_t slept = 0;
-            while (slept < data->sleep_time) {
-                if (ff_check_interrupt(&avf->interrupt_callback))
-                    return AVERROR_EXIT;
-                av_usleep(SLEEPTIME_10_MS);
-                slept += SLEEPTIME_10_MS;
-            }
-        }
-
-        if (!ret) {
-            ctx->pts_written[ctx->pts_written_nr++] = pkt->pts;
-            av_packet_unref(pkt);
-        }
-    }
-    return ret;
-}
-
-static int failing_write_trailer(AVFormatContext *avf)
-{
-    FailingMuxerContext *ctx = avf->priv_data;
-    return ctx->write_trailer_ret;
-}
-
-static void failing_deinit(AVFormatContext *avf)
-{
-    int i;
-    FailingMuxerContext *ctx = avf->priv_data;
-
-    if (!ctx->print_deinit_summary)
-        return;
-
-    printf("flush count: %d\n", ctx->flush_count);
-    printf("pts seen nr: %d\n", ctx->pts_written_nr);
-    printf("pts seen: ");
-    for (i = 0; i < ctx->pts_written_nr; ++i ) {
-        printf(i ? ",%d" : "%d", ctx->pts_written[i]);
-    }
-    printf("\n");
-}
-#define OFFSET(x) offsetof(FailingMuxerContext, x)
-static const AVOption options[] = {
-        {"write_header_ret", "write_header() return value", OFFSET(write_header_ret),
-         AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM},
-        {"write_trailer_ret", "write_trailer() return value", OFFSET(write_trailer_ret),
-         AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM},
-        {"print_deinit_summary", "print summary when deinitializing muxer", OFFSET(print_deinit_summary),
-         AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},
-        {NULL}
-    };
-
-static const AVClass failing_muxer_class = {
-    .class_name = "Fifo test muxer",
-    .item_name  = av_default_item_name,
-    .option     = options,
-    .version    = LIBAVUTIL_VERSION_INT,
-};
-
-const FFOutputFormat ff_fifo_test_muxer = {
-    .p.name         = "fifo_test",
-    .p.long_name    = NULL_IF_CONFIG_SMALL("Fifo test muxer"),
-    .priv_data_size = sizeof(FailingMuxerContext),
-    .write_header   = failing_write_header,
-    .write_packet   = failing_write_packet,
-    .write_trailer  = failing_write_trailer,
-    .deinit         = failing_deinit,
-    .p.priv_class   = &failing_muxer_class,
-#if FF_API_ALLOW_FLUSH
-    .p.flags        = AVFMT_NOFILE | AVFMT_ALLOW_FLUSH,
-#else
-    .p.flags        = AVFMT_NOFILE,
-#endif
-    .flags_internal = FF_FMT_ALLOW_FLUSH,
-};
-

libavformat/tests/fifo_muxer.c

@@ -23,8 +23,21 @@
 #include "libavutil/opt.h"
 #include "libavutil/time.h"
 #include "libavformat/avformat.h"
-#include "libavformat/url.h"
+#include "libavformat/mux.h"
 #include "libavformat/network.h"
+#include "libavformat/url.h"
+
+/*
+ * Include fifo.c directly to override libavformat/fifo.c and
+ * thereby prevent libavformat/fifo.o from being pulled in when linking.
+ * This relies on libavformat always being linked statically to its
+ * test tools (like this one).
+ * Due to FIFO_TEST, our fifo muxer will include special handling
+ * for tests, i.e. it allows to select the fifo_test muxer below
+ * even though it is not accessible via the API.
+ */
+#define FIFO_TEST
+#include "libavformat/fifo.c"
 
 #define MAX_TST_PACKETS 128
 #define SLEEPTIME_50_MS 50000
@@ -38,6 +51,118 @@ typedef struct FailingMuxerPacketData {
     unsigned sleep_time; /* sleep for this long in write_packet to simulate long I/O operation */
 } FailingMuxerPacketData;
 
+typedef struct FifoTestMuxerContext {
+    AVClass *class;
+    int write_header_ret;
+    int write_trailer_ret;
+    /* If non-zero, summary of processed packets will be printed in deinit */
+    int print_deinit_summary;
+
+    int flush_count;
+    int pts_written[MAX_TST_PACKETS];
+    int pts_written_nr;
+} FifoTestMuxerContext;
+
+static int fifo_test_header(AVFormatContext *avf)
+{
+    FifoTestMuxerContext *ctx = avf->priv_data;
+    return ctx->write_header_ret;
+}
+
+static int fifo_test_packet(AVFormatContext *avf, AVPacket *pkt)
+{
+    FifoTestMuxerContext *ctx = avf->priv_data;
+    int ret = 0;
+    if (!pkt) {
+        ctx->flush_count++;
+    } else {
+        FailingMuxerPacketData *data = (FailingMuxerPacketData*) pkt->data;
+
+        if (!data->recover_after) {
+            data->ret = 0;
+        } else {
+            data->recover_after--;
+        }
+
+        ret = data->ret;
+
+        if (data->sleep_time) {
+            int64_t slept = 0;
+            while (slept < data->sleep_time) {
+                if (ff_check_interrupt(&avf->interrupt_callback))
+                    return AVERROR_EXIT;
+                av_usleep(SLEEPTIME_10_MS);
+                slept += SLEEPTIME_10_MS;
+            }
+        }
+
+        if (!ret) {
+            ctx->pts_written[ctx->pts_written_nr++] = pkt->pts;
+            av_packet_unref(pkt);
+        }
+    }
+    return ret;
+}
+
+static int fifo_test_trailer(AVFormatContext *avf)
+{
+    FifoTestMuxerContext *ctx = avf->priv_data;
+    return ctx->write_trailer_ret;
+}
+
+static void failing_deinit(AVFormatContext *avf)
+{
+    int i;
+    FifoTestMuxerContext *ctx = avf->priv_data;
+
+    if (!ctx->print_deinit_summary)
+        return;
+
+    printf("flush count: %d\n", ctx->flush_count);
+    printf("pts seen nr: %d\n", ctx->pts_written_nr);
+    printf("pts seen: ");
+    for (i = 0; i < ctx->pts_written_nr; ++i ) {
+        printf(i ? ",%d" : "%d", ctx->pts_written[i]);
+    }
+    printf("\n");
+}
+
+#define OFF(x) offsetof(FifoTestMuxerContext, x)
+static const AVOption fifo_test_options[] = {
+        {"write_header_ret", "write_header() return value", OFF(write_header_ret),
+         AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM},
+        {"write_trailer_ret", "write_trailer() return value", OFF(write_trailer_ret),
+         AV_OPT_TYPE_INT, {.i64 = 0}, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM},
+        {"print_deinit_summary", "print summary when deinitializing muxer", OFF(print_deinit_summary),
+         AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},
+        {NULL}
+    };
+
+static const AVClass failing_muxer_class = {
+    .class_name = "Fifo test muxer",
+    .item_name  = av_default_item_name,
+    .option     = fifo_test_options,
+    .version    = LIBAVUTIL_VERSION_INT,
+};
+
+const FFOutputFormat ff_fifo_test_muxer = {
+    .p.name         = "fifo_test",
+    .p.long_name    = NULL_IF_CONFIG_SMALL("Fifo test muxer"),
+    .priv_data_size = sizeof(FifoTestMuxerContext),
+    .write_header   = fifo_test_header,
+    .write_packet   = fifo_test_packet,
+    .write_trailer  = fifo_test_trailer,
+    .deinit         = failing_deinit,
+    .p.priv_class   = &failing_muxer_class,
+#if FF_API_ALLOW_FLUSH
+    .p.flags        = AVFMT_NOFILE | AVFMT_ALLOW_FLUSH,
+#else
+    .p.flags        = AVFMT_NOFILE,
+#endif
+    .flags_internal = FF_FMT_ALLOW_FLUSH,
+};
+
+
 static int prepare_packet(AVPacket *pkt, const FailingMuxerPacketData *pkt_data, int64_t pts)
 {
     int ret = av_new_packet(pkt, sizeof(*pkt_data));