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gstreamer/gst-libs/gst/basecamerabinsrc/gstcamerabinpreview.c
Tim-Philipp Müller b6411ae74c libs: fix API export/import and 'inconsistent linkage' on MSVC 
For each lib we build export its own API in headers when we're
building it, otherwise import the API from the headers.

This fixes linker warnings on Windows when building with MSVC.

The problem was that we had defined all GST_*_API decorators
unconditionally to GST_EXPORT. This was intentional and only
supposed to be temporary, but caused linker warnings because
we tell the linker that we want to export all symbols even
those from externall DLLs, and when the linker notices that
they were in external DLLS and not present locally it warns.

What we need to do when building each library is: export
the library's own symbols and import all other symbols. To
this end we define e.g. BUILDING_GST_FOO and then we define
the GST_FOO_API decorator either to export or to import
symbols depending on whether BUILDING_GST_FOO is set or not.
That way external users of each library API automatically
get the import.

While we're at it, add new GST_API_EXPORT in config.h and use
that for GST_*_API decorators instead of GST_EXPORT.

The right export define depends on the toolchain and whether
we're using -fvisibility=hidden or not, so it's better to set it
to the right thing directly than hard-coding a compiler whitelist
in the public header.

We put the export define into config.h instead of passing it via the
command line to the compiler because it might contain spaces and brackets
and in the autotools scenario we'd have to pass that through multiple
layers of plumbing and Makefile/shell escaping and we're just not going
to be *that* lucky.

The export define is only used if we're compiling our lib, not by external
users of the lib headers, so it's not a problem to put it into config.h

Also, this means all .c files of libs need to include config.h
to get the export marker defined, so fix up a few that didn't
include config.h.

This commit depends on a common submodule commit that makes gst-glib-gen.mak
add an #include "config.h" to generated enum/marshal .c files for the
autotools build.

https://bugzilla.gnome.org/show_bug.cgi?id=797185
2018-09-24 14:45:56 +01:00

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/*
* GStreamer
* Copyright (C) 2008 Nokia Corporation <multimedia@maemo.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:camerabingeneral
* @short_description: helper functions for #GstCameraBin and it's modules
*
* Common helper functions for #GstCameraBin, #GstCameraBinImage and
* #GstCameraBinVideo.
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gst/app/gstappsrc.h>
#include <gst/app/gstappsink.h>
#include <gst/glib-compat-private.h>
#include "gstcamerabinpreview.h"
#include "gstbasecamerasrc.h"
GST_DEBUG_CATEGORY_EXTERN (base_camera_src_debug);
#define GST_CAT_DEFAULT base_camera_src_debug
static void _gst_camerabin_preview_set_caps (GstCameraBinPreviewPipelineData *
preview, GstCaps * caps);
static gboolean
bus_callback (GstBus * bus, GstMessage * message, gpointer user_data)
{
switch (GST_MESSAGE_TYPE (message)) {
case GST_MESSAGE_ERROR:{
GError *err;
GstCameraBinPreviewPipelineData *data;
data = user_data;
gst_message_parse_error (message, &err, NULL);
GST_WARNING ("Error from preview pipeline: %s", err->message);
g_error_free (err);
/* TODO Not sure if we should post an Error or Warning here */
GST_ELEMENT_ERROR (data, CORE, FAILED,
("fatal error in preview pipeline, disposing the pipeline"), (NULL));
/* Possible error situations:
* 1) cond_wait pending. prevent deadlock by signalling the cond
* 2) preview_pipeline_post called with new buffer to handle. returns
* because data->pipeline is set to null
* 3) new preview caps incoming. returns because data->pipeline is null
*/
if (data->pipeline) {
gst_element_set_state (data->pipeline, GST_STATE_NULL);
gst_object_unref (data->pipeline);
data->pipeline = NULL;
}
g_cond_signal (&data->processing_cond);
break;
}
default:
break;
}
return TRUE;
}
static GstFlowReturn
gst_camerabin_preview_pipeline_new_sample (GstAppSink * appsink,
gpointer user_data)
{
GstSample *sample;
GstStructure *s;
GstMessage *msg;
GstCameraBinPreviewPipelineData *data;
data = user_data;
sample = gst_app_sink_pull_sample (appsink);
s = gst_structure_new (GST_BASE_CAMERA_SRC_PREVIEW_MESSAGE_NAME,
"sample", GST_TYPE_SAMPLE, sample, NULL);
gst_sample_unref (sample);
msg = gst_message_new_element (GST_OBJECT (data->element), s);
GST_DEBUG_OBJECT (data->element, "sending message with preview image");
if (gst_element_post_message (data->element, msg) == FALSE) {
GST_WARNING_OBJECT (data->element,
"This element has no bus, therefore no message sent!");
}
g_mutex_lock (&data->processing_lock);
data->processing--;
if (data->processing == 0)
g_cond_signal (&data->processing_cond);
g_mutex_unlock (&data->processing_lock);
return GST_FLOW_OK;
}
/**
* gst_camerabin_create_preview_pipeline:
* @element: Owner of this pipeline
* @filter: Custom filter to process preview data (an extra ref is taken)
*
* Creates a new previewing pipeline that can receive buffers
* to be posted as camerabin preview messages for @element
*
* Returns: The newly created #GstCameraBinPreviewPipelineData
*/
GstCameraBinPreviewPipelineData *
gst_camerabin_create_preview_pipeline (GstElement * element,
GstElement * filter)
{
GstCameraBinPreviewPipelineData *data;
GstElement *csp;
GstElement *vscale;
gboolean added = FALSE;
gboolean linkfail = FALSE;
GstBus *bus;
GstAppSinkCallbacks callbacks = { 0, };
data = g_new0 (GstCameraBinPreviewPipelineData, 1);
data->pipeline = gst_pipeline_new ("preview-pipeline");
data->appsrc = gst_element_factory_make ("appsrc", "preview-appsrc");
data->appsink = gst_element_factory_make ("appsink", "preview-appsink");
csp = gst_element_factory_make ("videoconvert", "preview-vconv");
vscale = gst_element_factory_make ("videoscale", "preview-vscale");
if (!data->appsrc || !data->appsink || !csp || !vscale) {
goto error;
}
g_object_set (data->appsrc, "emit-signals", FALSE, NULL);
g_object_set (data->appsink, "sync", FALSE, "enable-last-sample",
FALSE, NULL);
gst_bin_add_many (GST_BIN (data->pipeline), data->appsrc,
data->appsink, csp, vscale, NULL);
if (filter)
gst_bin_add (GST_BIN (data->pipeline), gst_object_ref (filter));
added = TRUE;
if (filter) {
linkfail |=
GST_PAD_LINK_FAILED (gst_element_link_pads_full (data->appsrc, "src",
filter, NULL, GST_PAD_LINK_CHECK_NOTHING));
linkfail |=
GST_PAD_LINK_FAILED (gst_element_link_pads_full (filter, NULL,
vscale, "sink", GST_PAD_LINK_CHECK_CAPS));
} else {
linkfail |=
GST_PAD_LINK_FAILED (gst_element_link_pads_full (data->appsrc, "src",
vscale, "sink", GST_PAD_LINK_CHECK_NOTHING));
}
linkfail |=
GST_PAD_LINK_FAILED (gst_element_link_pads_full (vscale, "src", csp,
"sink", GST_PAD_LINK_CHECK_NOTHING));
linkfail |=
GST_PAD_LINK_FAILED (gst_element_link_pads_full (csp, "src",
data->appsink, "sink", GST_PAD_LINK_CHECK_NOTHING));
if (linkfail) {
GST_WARNING ("Failed to link preview pipeline elements");
goto error;
}
callbacks.new_sample = gst_camerabin_preview_pipeline_new_sample;
gst_app_sink_set_callbacks ((GstAppSink *) data->appsink, &callbacks, data,
NULL);
bus = gst_pipeline_get_bus (GST_PIPELINE (data->pipeline));
gst_bus_add_watch (bus, bus_callback, data);
gst_object_unref (bus);
g_object_set (data->appsink, "sync", FALSE, NULL);
data->element = element;
data->filter = filter;
data->vscale = vscale;
g_mutex_init (&data->processing_lock);
g_cond_init (&data->processing_cond);
data->pending_preview_caps = NULL;
data->processing = 0;
return data;
error:
GST_WARNING ("Failed to create camerabin's preview pipeline");
if (!added) {
if (csp)
gst_object_unref (csp);
if (vscale)
gst_object_unref (vscale);
if (data->appsrc)
gst_object_unref (data->appsrc);
if (data->appsink)
gst_object_unref (data->appsink);
}
gst_camerabin_destroy_preview_pipeline (data);
return NULL;
}
/**
* gst_camerabin_destroy_preview_pipeline:
* @preview: the #GstCameraBinPreviewPipelineData
*
* Frees a #GstCameraBinPreviewPipelineData
*/
void
gst_camerabin_destroy_preview_pipeline (GstCameraBinPreviewPipelineData *
preview)
{
g_return_if_fail (preview != NULL);
g_mutex_clear (&preview->processing_lock);
g_cond_clear (&preview->processing_cond);
if (preview->pipeline) {
GstBus *bus;
gst_element_set_state (preview->pipeline, GST_STATE_NULL);
bus = gst_pipeline_get_bus (GST_PIPELINE (preview->pipeline));
gst_bus_remove_watch (bus);
gst_object_unref (bus);
gst_object_unref (preview->pipeline);
}
g_free (preview);
}
/**
* gst_camerabin_preview_pipeline_post:
* @preview: the #GstCameraBinPreviewPipelineData
* @sample: the sample to be posted as a preview
*
* Converts the @sample to the desired format and posts the preview
* message to the bus.
*
* Returns: %TRUE on success
*/
gboolean
gst_camerabin_preview_pipeline_post (GstCameraBinPreviewPipelineData * preview,
GstSample * sample)
{
g_return_val_if_fail (preview != NULL, FALSE);
g_return_val_if_fail (preview->pipeline != NULL, FALSE);
g_return_val_if_fail (sample, FALSE);
g_mutex_lock (&preview->processing_lock);
g_return_val_if_fail (preview->pipeline != NULL, FALSE);
if (preview->pending_preview_caps) {
if (preview->processing > 0) {
g_cond_wait (&preview->processing_cond, &preview->processing_lock);
}
_gst_camerabin_preview_set_caps (preview, preview->pending_preview_caps);
gst_caps_replace (&preview->pending_preview_caps, NULL);
}
preview->processing++;
g_object_set (preview->appsrc, "caps", gst_sample_get_caps (sample), NULL);
gst_app_src_push_buffer ((GstAppSrc *) preview->appsrc,
gst_buffer_ref (gst_sample_get_buffer (sample)));
g_mutex_unlock (&preview->processing_lock);
return TRUE;
}
static void
_gst_camerabin_preview_set_caps (GstCameraBinPreviewPipelineData * preview,
GstCaps * caps)
{
GstState state, pending;
GstStateChangeReturn ret;
g_return_if_fail (preview != NULL);
g_return_if_fail (preview->pipeline != NULL);
ret = gst_element_get_state (preview->pipeline, &state, &pending, 0);
if (ret == GST_STATE_CHANGE_FAILURE) {
/* make it try again */
state = GST_STATE_PLAYING;
pending = GST_STATE_VOID_PENDING;
}
gst_element_set_state (preview->pipeline, GST_STATE_NULL);
g_object_set (preview->appsink, "caps", caps, NULL);
if (pending != GST_STATE_VOID_PENDING)
state = pending;
gst_element_set_state (preview->pipeline, state);
}
/**
* gst_camerabin_preview_set_caps:
* @preview: the #GstCameraBinPreviewPipelineData
* @caps: the #GstCaps to be set (a new ref will be taken)
*
* The caps that preview buffers should have when posted
* on the bus
*/
void
gst_camerabin_preview_set_caps (GstCameraBinPreviewPipelineData * preview,
GstCaps * caps)
{
g_return_if_fail (preview != NULL);
g_mutex_lock (&preview->processing_lock);
if (preview->processing == 0) {
_gst_camerabin_preview_set_caps (preview, caps);
} else {
GST_DEBUG ("Preview pipeline busy, storing new caps as pending");
gst_caps_replace (&preview->pending_preview_caps, caps);
}
g_mutex_unlock (&preview->processing_lock);
}
/**
* gst_camerabin_preview_set_filter:
* @preview: the #GstCameraBinPreviewPipelineData
* @filter: Custom filter to process preview data (an extra ref is taken)
*
* Set the filter element into preview pipeline.
*
* Returns: %TRUE on success
*/
gboolean
gst_camerabin_preview_set_filter (GstCameraBinPreviewPipelineData * preview,
GstElement * filter)
{
gboolean ret = TRUE;
GstState current;
g_return_val_if_fail (preview != NULL, FALSE);
GST_DEBUG ("Preview pipeline setting new filter %p", filter);
g_mutex_lock (&preview->processing_lock);
gst_element_get_state (preview->pipeline, &current, NULL, 0);
if (preview->processing == 0 && current == GST_STATE_NULL) {
gboolean linkfail = FALSE;
if (preview->filter) {
/* Unlink and remove old filter */
gst_element_unlink (preview->appsrc, preview->filter);
gst_element_unlink (preview->filter, preview->vscale);
gst_bin_remove (GST_BIN (preview->pipeline), preview->filter);
} else {
/* Make room for filter by breaking the link between appsrc and vcale */
gst_element_unlink (preview->appsrc, preview->vscale);
}
if (filter) {
/* Add and link the new filter between appsrc and vscale */
gst_bin_add (GST_BIN (preview->pipeline), gst_object_ref (filter));
linkfail |=
GST_PAD_LINK_FAILED (gst_element_link_pads_full (preview->appsrc,
"src", filter, NULL, GST_PAD_LINK_CHECK_NOTHING));
linkfail |=
GST_PAD_LINK_FAILED (gst_element_link_pads_full (filter, NULL,
preview->vscale, "sink", GST_PAD_LINK_CHECK_CAPS));
} else {
/* No filter was given. Just link the appsrc to vscale directly */
linkfail |=
GST_PAD_LINK_FAILED (gst_element_link_pads_full (preview->appsrc,
"src", preview->vscale, "sink", GST_PAD_LINK_CHECK_NOTHING));
}
if (linkfail) {
GST_WARNING ("Linking the filter to pipeline failed");
ret = FALSE;
} else {
GST_DEBUG ("Linking the filter to pipeline successful");
preview->filter = filter;
}
} else {
GST_WARNING ("Cannot change filter when pipeline is running");
ret = FALSE;
}
g_mutex_unlock (&preview->processing_lock);
return ret;
}
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