[libcamera-devel] [PATCH 2/2] libcamera: geometry: Mark const functions with __nodiscard
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Thu Feb 4 04:59:51 CET 2021
Geometry classes generally have two sets of functions, one that operates
on the object and modifies it (e.g. Rectangle::scaleBy()), and one that
performs the same operations by instead return a modified copy of the
object, leaving the original untouched (e.g.Rectangle::scaledBy()). As
the names are close, they can easily be mistaken, with the const version
used instead of the in-place version.
To catch these errors at compile time, mark the const versions with
__nodiscard, as there is no use case for calling them without using the
result of the call.
Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
include/libcamera/geometry.h | 29 ++++++++++++++++-------------
1 file changed, 16 insertions(+), 13 deletions(-)
diff --git a/include/libcamera/geometry.h b/include/libcamera/geometry.h
index 2f3a82e2afc3..fdd1b4678074 100644
--- a/include/libcamera/geometry.h
+++ b/include/libcamera/geometry.h
@@ -11,6 +11,8 @@
#include <algorithm>
#include <string>
+#include <libcamera/compiler.h>
+
namespace libcamera {
class Rectangle;
@@ -92,8 +94,8 @@ public:
return *this;
}
- constexpr Size alignedDownTo(unsigned int hAlignment,
- unsigned int vAlignment) const
+ __nodiscard constexpr Size alignedDownTo(unsigned int hAlignment,
+ unsigned int vAlignment) const
{
return {
width / hAlignment * hAlignment,
@@ -101,8 +103,8 @@ public:
};
}
- constexpr Size alignedUpTo(unsigned int hAlignment,
- unsigned int vAlignment) const
+ __nodiscard constexpr Size alignedUpTo(unsigned int hAlignment,
+ unsigned int vAlignment) const
{
return {
(width + hAlignment - 1) / hAlignment * hAlignment,
@@ -110,7 +112,7 @@ public:
};
}
- constexpr Size boundedTo(const Size &bound) const
+ __nodiscard constexpr Size boundedTo(const Size &bound) const
{
return {
std::min(width, bound.width),
@@ -118,7 +120,7 @@ public:
};
}
- constexpr Size expandedTo(const Size &expand) const
+ __nodiscard constexpr Size expandedTo(const Size &expand) const
{
return {
std::max(width, expand.width),
@@ -126,10 +128,10 @@ public:
};
}
- Size boundedToAspectRatio(const Size &ratio) const;
- Size expandedToAspectRatio(const Size &ratio) const;
+ __nodiscard Size boundedToAspectRatio(const Size &ratio) const;
+ __nodiscard Size expandedToAspectRatio(const Size &ratio) const;
- Rectangle centeredTo(const Point ¢er) const;
+ __nodiscard Rectangle centeredTo(const Point ¢er) const;
Size operator*(float factor) const;
Size operator/(float factor) const;
@@ -247,10 +249,11 @@ public:
Rectangle &scaleBy(const Size &numerator, const Size &denominator);
Rectangle &translateBy(const Point &point);
- Rectangle boundedTo(const Rectangle &bound) const;
- Rectangle enclosedIn(const Rectangle &boundary) const;
- Rectangle scaledBy(const Size &numerator, const Size &denominator) const;
- Rectangle translatedBy(const Point &point) const;
+ __nodiscard Rectangle boundedTo(const Rectangle &bound) const;
+ __nodiscard Rectangle enclosedIn(const Rectangle &boundary) const;
+ __nodiscard Rectangle scaledBy(const Size &numerator,
+ const Size &denominator) const;
+ __nodiscard Rectangle translatedBy(const Point &point) const;
};
bool operator==(const Rectangle &lhs, const Rectangle &rhs);
--
Regards,
Laurent Pinchart
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