From 3e3c5205dbde6e53a0d3ecc69716b23447737de8 Mon Sep 17 00:00:00 2001
From: Tony Jinwoo Ahn <tony.jinwoo.ahn@gmail.com>
Date: Sun, 15 Dec 2019 08:36:56 +0000
Subject: [PATCH] gstreamer-video/video_info: Change functions from returning
 Option to Result

Partial work for:
https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/issues/216
---
 examples/src/bin/glupload.rs      |  4 ++--
 gstreamer-video/src/video_info.rs | 28 ++++++++++++++++------------
 2 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/examples/src/bin/glupload.rs b/examples/src/bin/glupload.rs
index 5038ce238..e139d1dc8 100644
--- a/examples/src/bin/glupload.rs
+++ b/examples/src/bin/glupload.rs
@@ -499,7 +499,7 @@ impl App {
 
                         let _info = sample
                             .get_caps()
-                            .and_then(|caps| gst_video::VideoInfo::from_caps(caps))
+                            .and_then(|caps| gst_video::VideoInfo::from_caps(caps).ok())
                             .ok_or_else(|| {
                                 gst_element_error!(
                                     appsink,
@@ -652,7 +652,7 @@ fn main_loop(mut app: App) -> Result<glutin::WindowedContext<glutin::PossiblyCur
             let buffer = sample.get_buffer_owned().unwrap();
             let info = sample
                 .get_caps()
-                .and_then(|caps| gst_video::VideoInfo::from_caps(caps))
+                .and_then(|caps| gst_video::VideoInfo::from_caps(caps).ok())
                 .unwrap();
 
             {
diff --git a/gstreamer-video/src/video_info.rs b/gstreamer-video/src/video_info.rs
index 218fdba88..ebaa91cf1 100644
--- a/gstreamer-video/src/video_info.rs
+++ b/gstreamer-video/src/video_info.rs
@@ -263,7 +263,7 @@ pub struct VideoInfoBuilder<'a> {
 }
 
 impl<'a> VideoInfoBuilder<'a> {
-    pub fn build(self) -> Option<VideoInfo> {
+    pub fn build(self) -> Result<VideoInfo, glib::error::BoolError> {
         unsafe {
             let mut info = mem::MaybeUninit::uninit();
 
@@ -306,13 +306,13 @@ impl<'a> VideoInfoBuilder<'a> {
             };
 
             if !res {
-                return None;
+                return Err(glib_bool_error!("Failed to build VideoInfo"));
             }
 
             let mut info = info.assume_init();
 
             if info.finfo.is_null() || info.width <= 0 || info.height <= 0 {
-                return None;
+                return Err(glib_bool_error!("Failed to build VideoInfo"));
             }
 
             if let Some(flags) = self.flags {
@@ -347,7 +347,7 @@ impl<'a> VideoInfoBuilder<'a> {
 
             if let Some(offset) = self.offset {
                 if offset.len() != ((*info.finfo).n_planes as usize) {
-                    return None;
+                    return Err(glib_bool_error!("Failed to build VideoInfo"));
                 }
 
                 let n_planes = (*info.finfo).n_planes as usize;
@@ -356,7 +356,7 @@ impl<'a> VideoInfoBuilder<'a> {
 
             if let Some(stride) = self.stride {
                 if stride.len() != ((*info.finfo).n_planes as usize) {
-                    return None;
+                    return Err(glib_bool_error!("Failed to build VideoInfo"));
                 }
 
                 let n_planes = (*info.finfo).n_planes as usize;
@@ -381,7 +381,7 @@ impl<'a> VideoInfoBuilder<'a> {
                 }
             }
 
-            Some(VideoInfo(info))
+            Ok(VideoInfo(info))
         }
     }
 
@@ -526,7 +526,7 @@ impl VideoInfo {
         }
     }
 
-    pub fn from_caps(caps: &gst::CapsRef) -> Option<Self> {
+    pub fn from_caps(caps: &gst::CapsRef) -> Result<Self, glib::error::BoolError> {
         skip_assert_initialized!();
 
         unsafe {
@@ -535,18 +535,22 @@ impl VideoInfo {
                 info.as_mut_ptr(),
                 caps.as_ptr(),
             )) {
-                Some(VideoInfo(info.assume_init()))
+                Ok(VideoInfo(info.assume_init()))
             } else {
-                None
+                Err(glib_bool_error!("Failed to create VideoInfo from caps"))
             }
         }
     }
 
-    pub fn to_caps(&self) -> Option<gst::Caps> {
+    pub fn to_caps(&self) -> Result<gst::Caps, glib::error::BoolError> {
         unsafe {
-            from_glib_full(gst_video_sys::gst_video_info_to_caps(
+            let result = from_glib_full(gst_video_sys::gst_video_info_to_caps(
                 &self.0 as *const _ as *mut _,
-            ))
+            ));
+            match result {
+                Some(c) => Ok(c),
+                None => Err(glib_bool_error!("Failed to create caps from VideoInfo")),
+            }
         }
     }