[PATCH 1/3] libcamera: media_object: Add MediaLink string representations

[Kieran Bingham]

Various parts of libcamera print the representation of a MediaLink by
inline joining the parts to make a string representation.

This repeated use case can be supported with a common helper to print
the MediaLink in a common manner using the existing toString() and
operator<< overload style to make it easier to report on MediaLink
types.

This implementation will report in the following style:

  'imx283 1-001a'[0] -> 'video-mux'[0]

Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---
 include/libcamera/internal/media_object.h |  4 ++++
 src/libcamera/media_object.cpp            | 25 +++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/include/libcamera/internal/media_object.h b/include/libcamera/internal/media_object.h
index c9d77511a991..3ebef938bc49 100644
--- a/include/libcamera/internal/media_object.h
+++ b/include/libcamera/internal/media_object.h
@@ -48,6 +48,8 @@ public:
 	unsigned int flags() const { return flags_; }
 	int setEnabled(bool enable);
 
+	std::string toString() const;
+
 private:
 	LIBCAMERA_DISABLE_COPY_AND_MOVE(MediaLink)
 
@@ -61,6 +63,8 @@ private:
 	unsigned int flags_;
 };
 
+std::ostream &operator<<(std::ostream &out, const MediaLink &link);
+
 class MediaPad : public MediaObject
 {
 public:
diff --git a/src/libcamera/media_object.cpp b/src/libcamera/media_object.cpp
index 1b191a1e4df8..fa2c44b0abb6 100644
--- a/src/libcamera/media_object.cpp
+++ b/src/libcamera/media_object.cpp
@@ -146,6 +146,31 @@ MediaLink::MediaLink(const struct media_v2_link *link, MediaPad *source,
 {
 }
 
+std::string MediaLink::toString() const
+{
+	std::stringstream ss;
+	ss << *this;
+
+	return ss.str();
+}
+
+/**
+ * \brief Insert a text representation of a Link into an output stream
+ * \param[in] out The output stream
+ * \param[in] r The MediaLink
+ * \return The output stream \a out
+ */
+std::ostream &operator<<(std::ostream &out, const MediaLink &link)
+{
+	out << "'"
+	    << link.source()->entity()->name() << "'["
+	    << link.source()->index() << "] -> '"
+	    << link.sink()->entity()->name() << "'["
+	    << link.sink()->index() << "]";
+
+	return out;
+}
+
 /**
  * \fn MediaLink::source()
  * \brief Retrieve the link's source pad
-- 
2.34.1