[RFC PATCH v1] treewide: Prefer `std::string_view` over `const std::string&` in parameters

Barnabás Pőcze pobrn at protonmail.com
Sun Dec 15 21:48:06 CET 2024


A parameter of type `const std::string&` is not the right choice in
almost all cases. It forces the caller to construct an `std::string`
if they don't already have one, and accessing its data requires
an extra indirection. Furthermore, `std::string` is just one
instantiation of `std::basic_string<>`, using e.g. a different
allocator would immediately make it incompatible.

In contrast to that using an `std::string_view` is better if
NUL termination is not needed since no `std::string` construction
is required, and in many cases it can be passed directly in registers.

Signed-off-by: Barnabás Pőcze <pobrn at protonmail.com>
---
 include/libcamera/base/utils.h                     | 10 +++++-----
 include/libcamera/camera_manager.h                 |  3 ++-
 .../libcamera/internal/camera_sensor_properties.h  |  4 ++--
 include/libcamera/internal/device_enumerator.h     |  3 ++-
 include/libcamera/internal/formats.h               |  3 ++-
 include/libcamera/internal/media_device.h          |  7 ++++---
 include/libcamera/internal/pipeline_handler.h      |  3 ++-
 include/libcamera/internal/v4l2_subdevice.h        |  3 ++-
 include/libcamera/internal/v4l2_videodevice.h      |  3 ++-
 include/libcamera/pixel_format.h                   |  3 ++-
 src/apps/cam/capture_script.cpp                    |  2 +-
 src/apps/cam/capture_script.h                      |  3 ++-
 src/apps/cam/drm.cpp                               |  8 ++++----
 src/apps/cam/drm.h                                 |  9 +++++----
 src/ipa/libipa/camera_sensor_helper.cpp            |  2 +-
 src/ipa/libipa/camera_sensor_helper.h              |  3 ++-
 src/ipa/libipa/module.cpp                          |  2 +-
 src/ipa/libipa/module.h                            |  4 ++--
 src/libcamera/base/utils.cpp                       |  8 ++++----
 src/libcamera/camera_manager.cpp                   |  2 +-
 src/libcamera/device_enumerator.cpp                |  2 +-
 src/libcamera/device_enumerator_udev.cpp           |  2 +-
 src/libcamera/formats.cpp                          |  2 +-
 src/libcamera/media_device.cpp                     | 14 +++++++-------
 src/libcamera/pipeline_handler.cpp                 |  2 +-
 src/libcamera/pixel_format.cpp                     |  2 +-
 src/libcamera/sensor/camera_sensor_properties.cpp  |  4 ++--
 src/libcamera/v4l2_subdevice.cpp                   |  2 +-
 src/libcamera/v4l2_videodevice.cpp                 |  2 +-
 src/py/libcamera/py_camera_manager.h               |  2 +-
 src/py/libcamera/py_main.cpp                       |  2 +-
 31 files changed, 66 insertions(+), 55 deletions(-)

diff --git a/include/libcamera/base/utils.h b/include/libcamera/base/utils.h
index 780aeda6a..3b8b3dea9 100644
--- a/include/libcamera/base/utils.h
+++ b/include/libcamera/base/utils.h
@@ -38,7 +38,7 @@ namespace utils {
 const char *basename(const char *path);
 
 char *secure_getenv(const char *name);
-std::string dirname(const std::string &path);
+std::string dirname(std::string_view path);
 
 template<typename T>
 std::vector<typename T::key_type> map_keys(const T &map)
@@ -143,7 +143,7 @@ size_t strlcpy(char *dst, const char *src, size_t size);
 
 #ifndef __DOXYGEN__
 template<typename Container, typename UnaryOp>
-std::string join(const Container &items, const std::string &sep, UnaryOp op)
+std::string join(const Container &items, std::string_view sep, UnaryOp op)
 {
 	std::ostringstream ss;
 	bool first = true;
@@ -162,7 +162,7 @@ std::string join(const Container &items, const std::string &sep, UnaryOp op)
 }
 
 template<typename Container>
-std::string join(const Container &items, const std::string &sep)
+std::string join(const Container &items, std::string_view sep)
 {
 	std::ostringstream ss;
 	bool first = true;
@@ -181,7 +181,7 @@ std::string join(const Container &items, const std::string &sep)
 }
 #else
 template<typename Container, typename UnaryOp>
-std::string join(const Container &items, const std::string &sep, UnaryOp op = nullptr);
+std::string join(const Container &items, std::string_view sep, UnaryOp op = nullptr);
 #endif
 
 namespace details {
@@ -240,7 +240,7 @@ private:
 
 details::StringSplitter split(const std::string &str, const std::string &delim);
 
-std::string toAscii(const std::string &str);
+std::string toAscii(std::string_view str);
 
 std::string libcameraBuildPath();
 std::string libcameraSourcePath();
diff --git a/include/libcamera/camera_manager.h b/include/libcamera/camera_manager.h
index b50df7825..27835500f 100644
--- a/include/libcamera/camera_manager.h
+++ b/include/libcamera/camera_manager.h
@@ -9,6 +9,7 @@
 
 #include <memory>
 #include <string>
+#include <string_view>
 #include <sys/types.h>
 #include <vector>
 
@@ -31,7 +32,7 @@ public:
 	void stop();
 
 	std::vector<std::shared_ptr<Camera>> cameras() const;
-	std::shared_ptr<Camera> get(const std::string &id);
+	std::shared_ptr<Camera> get(std::string_view id);
 
 	static const std::string &version() { return version_; }
 
diff --git a/include/libcamera/internal/camera_sensor_properties.h b/include/libcamera/internal/camera_sensor_properties.h
index d7d4dab62..b44093906 100644
--- a/include/libcamera/internal/camera_sensor_properties.h
+++ b/include/libcamera/internal/camera_sensor_properties.h
@@ -9,7 +9,7 @@
 
 #include <map>
 #include <stdint.h>
-#include <string>
+#include <string_view>
 
 #include <libcamera/control_ids.h>
 #include <libcamera/geometry.h>
@@ -24,7 +24,7 @@ struct CameraSensorProperties {
 		uint8_t hblankDelay;
 	};
 
-	static const CameraSensorProperties *get(const std::string &sensor);
+	static const CameraSensorProperties *get(std::string_view sensor);
 
 	Size unitCellSize;
 	std::map<controls::draft::TestPatternModeEnum, int32_t> testPatternModes;
diff --git a/include/libcamera/internal/device_enumerator.h b/include/libcamera/internal/device_enumerator.h
index db3532a98..eecc39cfb 100644
--- a/include/libcamera/internal/device_enumerator.h
+++ b/include/libcamera/internal/device_enumerator.h
@@ -9,6 +9,7 @@
 
 #include <memory>
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include <libcamera/base/signal.h>
@@ -48,7 +49,7 @@ public:
 protected:
 	std::unique_ptr<MediaDevice> createDevice(const std::string &deviceNode);
 	void addDevice(std::unique_ptr<MediaDevice> media);
-	void removeDevice(const std::string &deviceNode);
+	void removeDevice(std::string_view deviceNode);
 
 private:
 	std::vector<std::shared_ptr<MediaDevice>> devices_;
diff --git a/include/libcamera/internal/formats.h b/include/libcamera/internal/formats.h
index 6a3e9c16a..bd7ac6ed1 100644
--- a/include/libcamera/internal/formats.h
+++ b/include/libcamera/internal/formats.h
@@ -8,6 +8,7 @@
 #pragma once
 
 #include <array>
+#include <string_view>
 #include <vector>
 
 #include <libcamera/geometry.h>
@@ -35,7 +36,7 @@ public:
 
 	static const PixelFormatInfo &info(const PixelFormat &format);
 	static const PixelFormatInfo &info(const V4L2PixelFormat &format);
-	static const PixelFormatInfo &info(const std::string &name);
+	static const PixelFormatInfo &info(std::string_view name);
 
 	unsigned int stride(unsigned int width, unsigned int plane,
 			    unsigned int align = 1) const;
diff --git a/include/libcamera/internal/media_device.h b/include/libcamera/internal/media_device.h
index e412d3a0b..91610a7aa 100644
--- a/include/libcamera/internal/media_device.h
+++ b/include/libcamera/internal/media_device.h
@@ -9,6 +9,7 @@
 
 #include <map>
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include <linux/media.h>
@@ -44,10 +45,10 @@ public:
 	unsigned int hwRevision() const { return hwRevision_; }
 
 	const std::vector<MediaEntity *> &entities() const { return entities_; }
-	MediaEntity *getEntityByName(const std::string &name) const;
+	MediaEntity *getEntityByName(std::string_view name) const;
 
-	MediaLink *link(const std::string &sourceName, unsigned int sourceIdx,
-			const std::string &sinkName, unsigned int sinkIdx);
+	MediaLink *link(std::string_view sourceName, unsigned int sourceIdx,
+			std::string_view sinkName, unsigned int sinkIdx);
 	MediaLink *link(const MediaEntity *source, unsigned int sourceIdx,
 			const MediaEntity *sink, unsigned int sinkIdx);
 	MediaLink *link(const MediaPad *source, const MediaPad *sink);
diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h
index fb28a18d0..45eafce9b 100644
--- a/include/libcamera/internal/pipeline_handler.h
+++ b/include/libcamera/internal/pipeline_handler.h
@@ -10,6 +10,7 @@
 #include <memory>
 #include <queue>
 #include <string>
+#include <string_view>
 #include <sys/types.h>
 #include <vector>
 
@@ -112,7 +113,7 @@ public:
 	const std::string &name() const { return name_; }
 
 	static std::vector<PipelineHandlerFactoryBase *> &factories();
-	static const PipelineHandlerFactoryBase *getFactoryByName(const std::string &name);
+	static const PipelineHandlerFactoryBase *getFactoryByName(std::string_view name);
 
 private:
 	static void registerType(PipelineHandlerFactoryBase *factory);
diff --git a/include/libcamera/internal/v4l2_subdevice.h b/include/libcamera/internal/v4l2_subdevice.h
index 194382f84..d17365e14 100644
--- a/include/libcamera/internal/v4l2_subdevice.h
+++ b/include/libcamera/internal/v4l2_subdevice.h
@@ -11,6 +11,7 @@
 #include <optional>
 #include <ostream>
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include <linux/v4l2-subdev.h>
@@ -161,7 +162,7 @@ public:
 	const V4L2SubdeviceCapability &caps() const { return caps_; }
 
 	static std::unique_ptr<V4L2Subdevice>
-	fromEntityName(const MediaDevice *media, const std::string &entity);
+	fromEntityName(const MediaDevice *media, std::string_view entity);
 
 protected:
 	std::string logPrefix() const override;
diff --git a/include/libcamera/internal/v4l2_videodevice.h b/include/libcamera/internal/v4l2_videodevice.h
index f021c2a01..c256e82af 100644
--- a/include/libcamera/internal/v4l2_videodevice.h
+++ b/include/libcamera/internal/v4l2_videodevice.h
@@ -14,6 +14,7 @@
 #include <ostream>
 #include <stdint.h>
 #include <string>
+#include <string_view>
 #include <unordered_set>
 #include <vector>
 
@@ -228,7 +229,7 @@ public:
 	Signal<> dequeueTimeout;
 
 	static std::unique_ptr<V4L2VideoDevice>
-	fromEntityName(const MediaDevice *media, const std::string &entity);
+	fromEntityName(const MediaDevice *media, std::string_view entity);
 
 	V4L2PixelFormat toV4L2PixelFormat(const PixelFormat &pixelFormat) const;
 
diff --git a/include/libcamera/pixel_format.h b/include/libcamera/pixel_format.h
index 1b4d8c7c8..874b2528b 100644
--- a/include/libcamera/pixel_format.h
+++ b/include/libcamera/pixel_format.h
@@ -10,6 +10,7 @@
 #include <ostream>
 #include <stdint.h>
 #include <string>
+#include <string_view>
 
 namespace libcamera {
 
@@ -38,7 +39,7 @@ public:
 
 	std::string toString() const;
 
-	static PixelFormat fromString(const std::string &name);
+	static PixelFormat fromString(std::string_view name);
 
 private:
 	uint32_t fourcc_;
diff --git a/src/apps/cam/capture_script.cpp b/src/apps/cam/capture_script.cpp
index fc1dfa75f..d4760ea78 100644
--- a/src/apps/cam/capture_script.cpp
+++ b/src/apps/cam/capture_script.cpp
@@ -432,7 +432,7 @@ std::vector<std::string> CaptureScript::parseSingleArray()
 	}
 }
 
-void CaptureScript::unpackFailure(const ControlId *id, const std::string &repr)
+void CaptureScript::unpackFailure(const ControlId *id, std::string_view repr)
 {
 	static const std::map<unsigned int, const char *> typeNames = {
 		{ ControlTypeNone, "none" },
diff --git a/src/apps/cam/capture_script.h b/src/apps/cam/capture_script.h
index 294b92036..fb40371f2 100644
--- a/src/apps/cam/capture_script.h
+++ b/src/apps/cam/capture_script.h
@@ -10,6 +10,7 @@
 #include <map>
 #include <memory>
 #include <string>
+#include <string_view>
 
 #include <libcamera/camera.h>
 #include <libcamera/controls.h>
@@ -67,7 +68,7 @@ private:
 	std::vector<std::string> parseSingleArray();
 
 	void unpackFailure(const libcamera::ControlId *id,
-			   const std::string &repr);
+			   std::string_view repr);
 	libcamera::ControlValue unpackControl(const libcamera::ControlId *id);
 	libcamera::Rectangle unpackRectangle(const std::vector<std::string> &strVec);
 };
diff --git a/src/apps/cam/drm.cpp b/src/apps/cam/drm.cpp
index 47bbb6b05..fd9c59ec4 100644
--- a/src/apps/cam/drm.cpp
+++ b/src/apps/cam/drm.cpp
@@ -57,7 +57,7 @@ Object::~Object()
 {
 }
 
-const Property *Object::property(const std::string &name) const
+const Property *Object::property(std::string_view name) const
 {
 	for (const PropertyValue &pv : properties_) {
 		const Property *property = static_cast<const Property *>(dev_->object(pv.id()));
@@ -68,7 +68,7 @@ const Property *Object::property(const std::string &name) const
 	return nullptr;
 }
 
-const PropertyValue *Object::propertyValue(const std::string &name) const
+const PropertyValue *Object::propertyValue(std::string_view name) const
 {
 	for (const PropertyValue &pv : properties_) {
 		const Property *property = static_cast<const Property *>(dev_->object(pv.id()));
@@ -320,7 +320,7 @@ AtomicRequest::~AtomicRequest()
 		drmModeAtomicFree(request_);
 }
 
-int AtomicRequest::addProperty(const Object *object, const std::string &property,
+int AtomicRequest::addProperty(const Object *object, std::string_view property,
 			       uint64_t value)
 {
 	if (!valid_)
@@ -335,7 +335,7 @@ int AtomicRequest::addProperty(const Object *object, const std::string &property
 	return addProperty(object->id(), prop->id(), value);
 }
 
-int AtomicRequest::addProperty(const Object *object, const std::string &property,
+int AtomicRequest::addProperty(const Object *object, std::string_view property,
 			       std::unique_ptr<Blob> blob)
 {
 	if (!valid_)
diff --git a/src/apps/cam/drm.h b/src/apps/cam/drm.h
index 1ba83b6eb..aa1b06400 100644
--- a/src/apps/cam/drm.h
+++ b/src/apps/cam/drm.h
@@ -13,6 +13,7 @@
 #include <memory>
 #include <stdint.h>
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include <libcamera/base/signal.h>
@@ -57,8 +58,8 @@ public:
 	uint32_t id() const { return id_; }
 	Type type() const { return type_; }
 
-	const Property *property(const std::string &name) const;
-	const PropertyValue *propertyValue(const std::string &name) const;
+	const Property *property(std::string_view name) const;
+	const PropertyValue *propertyValue(std::string_view name) const;
 	const std::vector<PropertyValue> &properties() const { return properties_; }
 
 protected:
@@ -260,9 +261,9 @@ public:
 	Device *device() const { return dev_; }
 	bool isValid() const { return valid_; }
 
-	int addProperty(const Object *object, const std::string &property,
+	int addProperty(const Object *object, std::string_view property,
 			uint64_t value);
-	int addProperty(const Object *object, const std::string &property,
+	int addProperty(const Object *object, std::string_view property,
 			std::unique_ptr<Blob> blob);
 	int commit(unsigned int flags = 0);
 
diff --git a/src/ipa/libipa/camera_sensor_helper.cpp b/src/ipa/libipa/camera_sensor_helper.cpp
index 7c66cd57d..4ed050b14 100644
--- a/src/ipa/libipa/camera_sensor_helper.cpp
+++ b/src/ipa/libipa/camera_sensor_helper.cpp
@@ -240,7 +240,7 @@ CameraSensorHelperFactoryBase::CameraSensorHelperFactoryBase(const std::string n
  * corresponding to the named factory or a null pointer if no such factory
  * exists
  */
-std::unique_ptr<CameraSensorHelper> CameraSensorHelperFactoryBase::create(const std::string &name)
+std::unique_ptr<CameraSensorHelper> CameraSensorHelperFactoryBase::create(std::string_view name)
 {
 	const std::vector<CameraSensorHelperFactoryBase *> &factories =
 		CameraSensorHelperFactoryBase::factories();
diff --git a/src/ipa/libipa/camera_sensor_helper.h b/src/ipa/libipa/camera_sensor_helper.h
index a9300a64f..eedc80114 100644
--- a/src/ipa/libipa/camera_sensor_helper.h
+++ b/src/ipa/libipa/camera_sensor_helper.h
@@ -11,6 +11,7 @@
 #include <optional>
 #include <stdint.h>
 #include <string>
+#include <string_view>
 #include <variant>
 #include <vector>
 
@@ -56,7 +57,7 @@ public:
 	CameraSensorHelperFactoryBase(const std::string name);
 	virtual ~CameraSensorHelperFactoryBase() = default;
 
-	static std::unique_ptr<CameraSensorHelper> create(const std::string &name);
+	static std::unique_ptr<CameraSensorHelper> create(std::string_view name);
 
 	static std::vector<CameraSensorHelperFactoryBase *> &factories();
 
diff --git a/src/ipa/libipa/module.cpp b/src/ipa/libipa/module.cpp
index 64ca91419..91fb588e7 100644
--- a/src/ipa/libipa/module.cpp
+++ b/src/ipa/libipa/module.cpp
@@ -107,7 +107,7 @@ namespace ipa {
  */
 
 /**
- * \fn Module::createAlgorithm(const std::string &name)
+ * \fn Module::createAlgorithm(std::string_view name)
  * \brief Create an instance of an Algorithm by name
  * \param[in] name The algorithm name
  *
diff --git a/src/ipa/libipa/module.h b/src/ipa/libipa/module.h
index 0fb51916f..62c700a64 100644
--- a/src/ipa/libipa/module.h
+++ b/src/ipa/libipa/module.h
@@ -9,7 +9,7 @@
 
 #include <list>
 #include <memory>
-#include <string>
+#include <string_view>
 #include <vector>
 
 #include <libcamera/base/log.h>
@@ -95,7 +95,7 @@ private:
 		return 0;
 	}
 
-	static std::unique_ptr<Algorithm<Module>> createAlgorithm(const std::string &name)
+	static std::unique_ptr<Algorithm<Module>> createAlgorithm(std::string_view name)
 	{
 		for (const AlgorithmFactoryBase<Module> *factory : factories()) {
 			if (factory->name() == name)
diff --git a/src/libcamera/base/utils.cpp b/src/libcamera/base/utils.cpp
index bcfc1941a..de6e2afd6 100644
--- a/src/libcamera/base/utils.cpp
+++ b/src/libcamera/base/utils.cpp
@@ -80,7 +80,7 @@ char *secure_getenv(const char *name)
  *
  * \return A string of the directory component of the path
  */
-std::string dirname(const std::string &path)
+std::string dirname(std::string_view path)
 {
 	if (path.empty())
 		return ".";
@@ -116,7 +116,7 @@ std::string dirname(const std::string &path)
 		pos--;
 	}
 
-	return path.substr(0, pos + 1);
+	return std::string(path.substr(0, pos + 1));
 }
 
 /**
@@ -278,7 +278,7 @@ std::string details::StringSplitter::iterator::operator*() const
 
 /**
  * \fn template<typename Container, typename UnaryOp> \
- * std::string utils::join(const Container &items, const std::string &sep, UnaryOp op)
+ * std::string utils::join(const Container &items, std::string_view sep, UnaryOp op)
  * \brief Join elements of a container in a string with a separator
  * \param[in] items The container
  * \param[in] sep The separator to add between elements
@@ -319,7 +319,7 @@ details::StringSplitter split(const std::string &str, const std::string &delim)
  *
  * \return A string equal to \a str stripped out of all non-ASCII characters
  */
-std::string toAscii(const std::string &str)
+std::string toAscii(std::string_view str)
 {
 	std::string ret;
 	for (const char &c : str)
diff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp
index 87e6717ec..179fa37ea 100644
--- a/src/libcamera/camera_manager.cpp
+++ b/src/libcamera/camera_manager.cpp
@@ -382,7 +382,7 @@ std::vector<std::shared_ptr<Camera>> CameraManager::cameras() const
  *
  * \return Shared pointer to Camera object or nullptr if camera not found
  */
-std::shared_ptr<Camera> CameraManager::get(const std::string &id)
+std::shared_ptr<Camera> CameraManager::get(std::string_view id)
 {
 	Private *const d = _d();
 
diff --git a/src/libcamera/device_enumerator.cpp b/src/libcamera/device_enumerator.cpp
index ae17862f6..8744a90f3 100644
--- a/src/libcamera/device_enumerator.cpp
+++ b/src/libcamera/device_enumerator.cpp
@@ -272,7 +272,7 @@ void DeviceEnumerator::addDevice(std::unique_ptr<MediaDevice> media)
  * enumerator with addDevice(). The media device's MediaDevice::disconnected
  * signal is emitted.
  */
-void DeviceEnumerator::removeDevice(const std::string &deviceNode)
+void DeviceEnumerator::removeDevice(std::string_view deviceNode)
 {
 	std::shared_ptr<MediaDevice> media;
 
diff --git a/src/libcamera/device_enumerator_udev.cpp b/src/libcamera/device_enumerator_udev.cpp
index 4e20a3cc0..c330f30bc 100644
--- a/src/libcamera/device_enumerator_udev.cpp
+++ b/src/libcamera/device_enumerator_udev.cpp
@@ -351,7 +351,7 @@ void DeviceEnumeratorUdev::udevNotify()
 	} else if (action == "remove") {
 		const char *subsystem = udev_device_get_subsystem(dev);
 		if (subsystem && !strcmp(subsystem, "media"))
-			removeDevice(std::string(deviceNode));
+			removeDevice(deviceNode);
 	}
 
 	udev_device_unref(dev);
diff --git a/src/libcamera/formats.cpp b/src/libcamera/formats.cpp
index bfcdfc089..112dfe66b 100644
--- a/src/libcamera/formats.cpp
+++ b/src/libcamera/formats.cpp
@@ -1037,7 +1037,7 @@ const PixelFormatInfo &PixelFormatInfo::info(const V4L2PixelFormat &format)
  * \return The PixelFormatInfo describing the PixelFormat matching the
  * \a name if known, or an invalid PixelFormatInfo otherwise
  */
-const PixelFormatInfo &PixelFormatInfo::info(const std::string &name)
+const PixelFormatInfo &PixelFormatInfo::info(std::string_view name)
 {
 	for (const auto &info : pixelFormatInfo) {
 		if (info.second.name == name)
diff --git a/src/libcamera/media_device.cpp b/src/libcamera/media_device.cpp
index d71dad74d..131b34446 100644
--- a/src/libcamera/media_device.cpp
+++ b/src/libcamera/media_device.cpp
@@ -331,7 +331,7 @@ done:
  * \param[in] name The entity name
  * \return The entity with \a name, or nullptr if no such entity is found
  */
-MediaEntity *MediaDevice::getEntityByName(const std::string &name) const
+MediaEntity *MediaDevice::getEntityByName(std::string_view name) const
 {
 	for (MediaEntity *e : entities_)
 		if (e->name() == name)
@@ -359,8 +359,8 @@ MediaEntity *MediaDevice::getEntityByName(const std::string &name) const
  * \return The link that connects the two pads, or nullptr if no such a link
  * exists
  */
-MediaLink *MediaDevice::link(const std::string &sourceName, unsigned int sourceIdx,
-			     const std::string &sinkName, unsigned int sinkIdx)
+MediaLink *MediaDevice::link(std::string_view sourceName, unsigned int sourceIdx,
+			     std::string_view sinkName, unsigned int sinkIdx)
 {
 	const MediaEntity *source = getEntityByName(sourceName);
 	const MediaEntity *sink = getEntityByName(sinkName);
@@ -382,8 +382,8 @@ MediaLink *MediaDevice::link(const std::string &sourceName, unsigned int sourceI
  * entity \a source, to the pad at index \a sinkIdx of the sink entity \a
  * sink, if any.
  *
- * \sa link(const std::string &sourceName, unsigned int sourceIdx,
- *          const std::string &sinkName, unsigned int sinkIdx)
+ * \sa link(std::string_view sourceName, unsigned int sourceIdx,
+ *          std::string_view sinkName, unsigned int sinkIdx)
  * \sa link(const MediaPad *source, const MediaPad *sink)
  *
  * \return The link that connects the two pads, or nullptr if no such a link
@@ -406,8 +406,8 @@ MediaLink *MediaDevice::link(const MediaEntity *source, unsigned int sourceIdx,
  * \param[in] source The source pad
  * \param[in] sink The sink pad
  *
- * \sa link(const std::string &sourceName, unsigned int sourceIdx,
- *          const std::string &sinkName, unsigned int sinkIdx)
+ * \sa link(std::string_view sourceName, unsigned int sourceIdx,
+ *          std::string_view sinkName, unsigned int sinkIdx)
  * \sa link(const MediaEntity *source, unsigned int sourceIdx,
  *          const MediaEntity *sink, unsigned int sinkIdx)
  *
diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp
index caa5c20e7..6b395c666 100644
--- a/src/libcamera/pipeline_handler.cpp
+++ b/src/libcamera/pipeline_handler.cpp
@@ -852,7 +852,7 @@ std::vector<PipelineHandlerFactoryBase *> &PipelineHandlerFactoryBase::factories
  * \param[in] name The pipeline handler name
  * \return The factory of the pipeline with name \a name, or nullptr if not found
  */
-const PipelineHandlerFactoryBase *PipelineHandlerFactoryBase::getFactoryByName(const std::string &name)
+const PipelineHandlerFactoryBase *PipelineHandlerFactoryBase::getFactoryByName(std::string_view name)
 {
 	const std::vector<PipelineHandlerFactoryBase *> &factories =
 		PipelineHandlerFactoryBase::factories();
diff --git a/src/libcamera/pixel_format.cpp b/src/libcamera/pixel_format.cpp
index 314179a81..22f1520fd 100644
--- a/src/libcamera/pixel_format.cpp
+++ b/src/libcamera/pixel_format.cpp
@@ -135,7 +135,7 @@ std::string PixelFormat::toString() const
  * \return The PixelFormat represented by the \a name if known, or an
  * invalid pixel format otherwise.
  */
-PixelFormat PixelFormat::fromString(const std::string &name)
+PixelFormat PixelFormat::fromString(std::string_view name)
 {
 	return PixelFormatInfo::info(name).format;
 }
diff --git a/src/libcamera/sensor/camera_sensor_properties.cpp b/src/libcamera/sensor/camera_sensor_properties.cpp
index 2b06c5a1a..4283cacfa 100644
--- a/src/libcamera/sensor/camera_sensor_properties.cpp
+++ b/src/libcamera/sensor/camera_sensor_properties.cpp
@@ -78,9 +78,9 @@ LOG_DEFINE_CATEGORY(CameraSensorProperties)
  * \return A pointer to the CameraSensorProperties instance associated with a sensor
  * or nullptr if the sensor is not supported
  */
-const CameraSensorProperties *CameraSensorProperties::get(const std::string &sensor)
+const CameraSensorProperties *CameraSensorProperties::get(std::string_view sensor)
 {
-	static const std::map<std::string, const CameraSensorProperties> sensorProps = {
+	static const std::map<std::string_view, const CameraSensorProperties> sensorProps = {
 		{ "ar0144", {
 			.unitCellSize = { 3000, 3000 },
 			.testPatternModes = {
diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
index 3a0d075f9..7e85b33be 100644
--- a/src/libcamera/v4l2_subdevice.cpp
+++ b/src/libcamera/v4l2_subdevice.cpp
@@ -1688,7 +1688,7 @@ const std::string &V4L2Subdevice::model()
  */
 std::unique_ptr<V4L2Subdevice>
 V4L2Subdevice::fromEntityName(const MediaDevice *media,
-			      const std::string &entity)
+			      std::string_view entity)
 {
 	MediaEntity *mediaEntity = media->getEntityByName(entity);
 	if (!mediaEntity)
diff --git a/src/libcamera/v4l2_videodevice.cpp b/src/libcamera/v4l2_videodevice.cpp
index a5cf67845..834a1bd0d 100644
--- a/src/libcamera/v4l2_videodevice.cpp
+++ b/src/libcamera/v4l2_videodevice.cpp
@@ -2077,7 +2077,7 @@ void V4L2VideoDevice::watchdogExpired()
  */
 std::unique_ptr<V4L2VideoDevice>
 V4L2VideoDevice::fromEntityName(const MediaDevice *media,
-				const std::string &entity)
+				std::string_view entity)
 {
 	MediaEntity *mediaEntity = media->getEntityByName(entity);
 	if (!mediaEntity)
diff --git a/src/py/libcamera/py_camera_manager.h b/src/py/libcamera/py_camera_manager.h
index 3574db236..af69b915e 100644
--- a/src/py/libcamera/py_camera_manager.h
+++ b/src/py/libcamera/py_camera_manager.h
@@ -20,7 +20,7 @@ public:
 	~PyCameraManager();
 
 	pybind11::list cameras();
-	std::shared_ptr<Camera> get(const std::string &name) { return cameraManager_->get(name); }
+	std::shared_ptr<Camera> get(std::string_view name) { return cameraManager_->get(name); }
 
 	static const std::string &version() { return CameraManager::version(); }
 
diff --git a/src/py/libcamera/py_main.cpp b/src/py/libcamera/py_main.cpp
index 441a70ab4..820768c24 100644
--- a/src/py/libcamera/py_main.cpp
+++ b/src/py/libcamera/py_main.cpp
@@ -510,7 +510,7 @@ PYBIND11_MODULE(_libcamera, m)
 	pyPixelFormat
 		.def(py::init<>())
 		.def(py::init<uint32_t, uint64_t>())
-		.def(py::init<>([](const std::string &str) {
+		.def(py::init<>([](std::string_view str) {
 			return PixelFormat::fromString(str);
 		}))
 		.def_property_readonly("fourcc", &PixelFormat::fourcc)
-- 
2.47.1




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