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libcamera: yaml_parser: Replace ok flag to get() with std::optional

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The YamlObject::get() function takes a default value and an optional
bool ok flag to handle parsing errors. This ad-hoc mechanism complicates
error handling in callers.

A better API is possible by dropping the default value and ok flag and
returning an std::optional. Not only does it simplify the calls, it also
lets callers handle errors through the standard std::optional class
instead of the current ad-hoc mechanism.

Provide a get() wrapper around std::optional::value_or() to further
simplify callers that don't need any specific error handling.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Naushir Patuck <naush@raspberrypi.com>
Tested-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
This commit is contained in:
Laurent Pinchart
2022-07-26 04:33:19 +03:00
parent 22ffeae04d
commit feb8c9be78
3 changed files with 96 additions and 122 deletions
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src/libcamera/yaml_parser.cpp
+53 -85
View File
@@ -31,12 +31,6 @@ namespace {
/* Empty static YamlObject as a safe result for invalid operations */
static const YamlObject empty;
void setOk(bool *ok, bool result)
{
if (ok)
*ok = result;
}
} /* namespace */
/**
@@ -100,54 +94,52 @@ std::size_t YamlObject::size() const
}
/**
* \fn template<typename T> YamlObject::get<T>(
* const T &defaultValue, bool *ok) const
* \fn template<typename T> YamlObject::get<T>() const
* \brief Parse the YamlObject as a \a T value
* \param[in] defaultValue The default value when failing to parse
* \param[out] ok The result of whether the parse succeeded
*
* This function parses the value of the YamlObject as a \a T object, and
* returns the value. If parsing fails (usually because the YamlObject doesn't
* store a \a T value), the \a defaultValue is returned, and \a ok is set to
* false. Otherwise, the YamlObject value is returned, and \a ok is set to true.
* store a \a T value), std::nullopt is returned.
*
* The \a ok pointer is optional and can be a nullptr if the caller doesn't
* need to know if parsing succeeded.
* \return The YamlObject value, or std::nullopt if parsing failed
*/
/**
* \fn template<typename T> YamlObject::get<T>(const T &defaultValue) const
* \brief Parse the YamlObject as a \a T value
* \param[in] defaultValue The default value when failing to parse
*
* \return Value as a bool type
* This function parses the value of the YamlObject as a \a T object, and
* returns the value. If parsing fails (usually because the YamlObject doesn't
* store a \a T value), the \a defaultValue is returned.
*
* \return The YamlObject value, or \a defaultValue if parsing failed
*/
#ifndef __DOXYGEN__
template<>
bool YamlObject::get(const bool &defaultValue, bool *ok) const
std::optional<bool> YamlObject::get() const
{
setOk(ok, false);
if (type_ != Type::Value)
return defaultValue;
return {};
if (value_ == "true") {
setOk(ok, true);
if (value_ == "true")
return true;
} else if (value_ == "false") {
setOk(ok, true);
else if (value_ == "false")
return false;
}
return defaultValue;
return {};
}
template<>
int16_t YamlObject::get(const int16_t &defaultValue, bool *ok) const
std::optional<int16_t> YamlObject::get() const
{
setOk(ok, false);
if (type_ != Type::Value)
return defaultValue;
return {};
if (value_ == "")
return defaultValue;
return {};
char *end;
@@ -157,22 +149,19 @@ int16_t YamlObject::get(const int16_t &defaultValue, bool *ok) const
if ('\0' != *end || errno == ERANGE ||
value < std::numeric_limits<int16_t>::min() ||
value > std::numeric_limits<int16_t>::max())
return defaultValue;
return {};
setOk(ok, true);
return value;
}
template<>
uint16_t YamlObject::get(const uint16_t &defaultValue, bool *ok) const
std::optional<uint16_t> YamlObject::get() const
{
setOk(ok, false);
if (type_ != Type::Value)
return defaultValue;
return {};
if (value_ == "")
return defaultValue;
return {};
/*
* libyaml parses all scalar values as strings. When a string has
@@ -183,7 +172,7 @@ uint16_t YamlObject::get(const uint16_t &defaultValue, bool *ok) const
*/
std::size_t found = value_.find_first_not_of(" \t");
if (found != std::string::npos && value_[found] == '-')
return defaultValue;
return {};
char *end;
@@ -193,22 +182,19 @@ uint16_t YamlObject::get(const uint16_t &defaultValue, bool *ok) const
if ('\0' != *end || errno == ERANGE ||
value < std::numeric_limits<uint16_t>::min() ||
value > std::numeric_limits<uint16_t>::max())
return defaultValue;
return {};
setOk(ok, true);
return value;
}
template<>
int32_t YamlObject::get(const int32_t &defaultValue, bool *ok) const
std::optional<int32_t> YamlObject::get() const
{
setOk(ok, false);
if (type_ != Type::Value)
return defaultValue;
return {};
if (value_ == "")
return defaultValue;
return {};
char *end;
@@ -218,22 +204,19 @@ int32_t YamlObject::get(const int32_t &defaultValue, bool *ok) const
if ('\0' != *end || errno == ERANGE ||
value < std::numeric_limits<int32_t>::min() ||
value > std::numeric_limits<int32_t>::max())
return defaultValue;
return {};
setOk(ok, true);
return value;
}
template<>
uint32_t YamlObject::get(const uint32_t &defaultValue, bool *ok) const
std::optional<uint32_t> YamlObject::get() const
{
setOk(ok, false);
if (type_ != Type::Value)
return defaultValue;
return {};
if (value_ == "")
return defaultValue;
return {};
/*
* libyaml parses all scalar values as strings. When a string has
@@ -244,7 +227,7 @@ uint32_t YamlObject::get(const uint32_t &defaultValue, bool *ok) const
*/
std::size_t found = value_.find_first_not_of(" \t");
if (found != std::string::npos && value_[found] == '-')
return defaultValue;
return {};
char *end;
@@ -254,22 +237,19 @@ uint32_t YamlObject::get(const uint32_t &defaultValue, bool *ok) const
if ('\0' != *end || errno == ERANGE ||
value < std::numeric_limits<uint32_t>::min() ||
value > std::numeric_limits<uint32_t>::max())
return defaultValue;
return {};
setOk(ok, true);
return value;
}
template<>
double YamlObject::get(const double &defaultValue, bool *ok) const
std::optional<double> YamlObject::get() const
{
setOk(ok, false);
if (type_ != Type::Value)
return defaultValue;
return {};
if (value_ == "")
return defaultValue;
return {};
char *end;
@@ -277,50 +257,38 @@ double YamlObject::get(const double &defaultValue, bool *ok) const
double value = std::strtod(value_.c_str(), &end);
if ('\0' != *end || errno == ERANGE)
return defaultValue;
return {};
setOk(ok, true);
return value;
}
template<>
std::string YamlObject::get(const std::string &defaultValue, bool *ok) const
std::optional<std::string> YamlObject::get() const
{
setOk(ok, false);
if (type_ != Type::Value)
return defaultValue;
return {};
setOk(ok, true);
return value_;
}
template<>
Size YamlObject::get(const Size &defaultValue, bool *ok) const
std::optional<Size> YamlObject::get() const
{
setOk(ok, false);
if (type_ != Type::List)
return defaultValue;
return {};
if (list_.size() != 2)
return defaultValue;
return {};
/*
* Add a local variable to validate each dimension in case
* that ok == nullptr.
*/
bool valid;
uint32_t width = list_[0]->get<uint32_t>(0, &valid);
if (!valid)
return defaultValue;
auto width = list_[0]->get<uint32_t>();
if (!width)
return {};
uint32_t height = list_[1]->get<uint32_t>(0, &valid);
if (!valid)
return defaultValue;
auto height = list_[1]->get<uint32_t>();
if (!height)
return {};
setOk(ok, true);
return Size(width, height);
return Size(*width, *height);
}
#endif /* __DOXYGEN__ */