[libcamera-devel] [PATCH v7 01/14] libcamera: yaml_parser: Replace ok flag to get() with std::optional
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Wed Jul 27 04:38:03 CEST 2022
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 convenience 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 at ideasonboard.com>
---
include/libcamera/internal/yaml_parser.h | 9 +-
src/libcamera/yaml_parser.cpp | 138 +++++++++--------------
test/yaml-parser.cpp | 71 ++++++------
3 files changed, 96 insertions(+), 122 deletions(-)
diff --git a/include/libcamera/internal/yaml_parser.h b/include/libcamera/internal/yaml_parser.h
index 064cf44381d7..61f2223223a7 100644
--- a/include/libcamera/internal/yaml_parser.h
+++ b/include/libcamera/internal/yaml_parser.h
@@ -9,6 +9,7 @@
#include <iterator>
#include <map>
+#include <optional>
#include <string>
#include <vector>
@@ -165,7 +166,13 @@ public:
#else
template<typename T>
#endif
- T get(const T &defaultValue, bool *ok = nullptr) const;
+ std::optional<T> get() const;
+
+ template<typename T>
+ T get(const T &defaultValue) const
+ {
+ return get<T>().value_or(defaultValue);
+ }
DictAdapter asDict() const { return DictAdapter{ dictionary_ }; }
ListAdapter asList() const { return ListAdapter{ list_ }; }
diff --git a/src/libcamera/yaml_parser.cpp b/src/libcamera/yaml_parser.cpp
index 5c45e44e49c3..4299f5abd38a 100644
--- a/src/libcamera/yaml_parser.cpp
+++ b/src/libcamera/yaml_parser.cpp
@@ -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
+ *
+ * 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), std::nullopt is returned.
+ *
+ * \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
- * \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), the \a defaultValue 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 Value as a bool type
+ * \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__ */
diff --git a/test/yaml-parser.cpp b/test/yaml-parser.cpp
index 38f848232fa6..ebb654f2ef9c 100644
--- a/test/yaml-parser.cpp
+++ b/test/yaml-parser.cpp
@@ -148,7 +148,6 @@ protected:
}
/* Test string object */
- bool ok;
auto &strObj = (*root)["string"];
if (strObj.isDictionary()) {
@@ -161,27 +160,27 @@ protected:
return TestFail;
}
- if (strObj.get<string>("", &ok) != "libcamera" || !ok) {
+ if (strObj.get<string>().value_or("") != "libcamera") {
cerr << "String object parse as wrong content" << std::endl;
return TestFail;
}
- if (strObj.get<int32_t>(-1, &ok) != -1 || ok) {
+ if (strObj.get<int32_t>()) {
cerr << "String object parse as integer" << std::endl;
return TestFail;
}
- if (strObj.get<uint32_t>(1, &ok) != 1 || ok) {
+ if (strObj.get<uint32_t>()) {
cerr << "String object parse as unsigned integer" << std::endl;
return TestFail;
}
- if (strObj.get<double>(1.0, &ok) != 1.0 || ok) {
+ if (strObj.get<double>()) {
cerr << "String object parse as double" << std::endl;
return TestFail;
}
- if (strObj.get<Size>(Size(0, 0), &ok) != Size(0, 0) || ok) {
+ if (strObj.get<Size>()) {
cerr << "String object parse as Size" << std::endl;
return TestFail;
}
@@ -199,27 +198,27 @@ protected:
return TestFail;
}
- if (int32Obj.get<int32_t>(-100, &ok) != -100 || !ok) {
+ if (int32Obj.get<int32_t>().value_or(0) != -100) {
cerr << "Integer object parse as wrong value" << std::endl;
return TestFail;
}
- if (int32Obj.get<string>("", &ok) != "-100" || !ok) {
+ if (int32Obj.get<string>().value_or("") != "-100") {
cerr << "Integer object fail to parse as string" << std::endl;
return TestFail;
}
- if (int32Obj.get<double>(1.0, &ok) != -100.0 || !ok) {
+ if (int32Obj.get<double>().value_or(0.0) != -100.0) {
cerr << "Integer object fail to parse as double" << std::endl;
return TestFail;
}
- if (int32Obj.get<uint32_t>(1, &ok) != 1 || ok) {
+ if (int32Obj.get<uint32_t>()) {
cerr << "Negative integer object parse as unsigned integer" << std::endl;
return TestFail;
}
- if (int32Obj.get<Size>(Size(0, 0), &ok) != Size(0, 0) || ok) {
+ if (int32Obj.get<Size>()) {
cerr << "Integer object parse as Size" << std::endl;
return TestFail;
}
@@ -237,27 +236,27 @@ protected:
return TestFail;
}
- if (uint32Obj.get<int32_t>(-1, &ok) != 100 || !ok) {
+ if (uint32Obj.get<int32_t>().value_or(0) != 100) {
cerr << "Unsigned integer object fail to parse as integer" << std::endl;
return TestFail;
}
- if (uint32Obj.get<string>("", &ok) != "100" || !ok) {
+ if (uint32Obj.get<string>().value_or("") != "100") {
cerr << "Unsigned integer object fail to parse as string" << std::endl;
return TestFail;
}
- if (uint32Obj.get<double>(1.0, &ok) != 100.0 || !ok) {
+ if (uint32Obj.get<double>().value_or(0.0) != 100.0) {
cerr << "Unsigned integer object fail to parse as double" << std::endl;
return TestFail;
}
- if (uint32Obj.get<uint32_t>(100, &ok) != 100 || !ok) {
+ if (uint32Obj.get<uint32_t>().value_or(0) != 100) {
cerr << "Unsigned integer object parsed as wrong value" << std::endl;
return TestFail;
}
- if (uint32Obj.get<Size>(Size(0, 0), &ok) != Size(0, 0) || ok) {
+ if (uint32Obj.get<Size>()) {
cerr << "Unsigned integer object parsed as Size" << std::endl;
return TestFail;
}
@@ -275,27 +274,27 @@ protected:
return TestFail;
}
- if (doubleObj.get<string>("", &ok) != "3.14159" || !ok) {
+ if (doubleObj.get<string>().value_or("") != "3.14159") {
cerr << "Double object fail to parse as string" << std::endl;
return TestFail;
}
- if (doubleObj.get<double>(1.0, &ok) != 3.14159 || !ok) {
+ if (doubleObj.get<double>().value_or(0.0) != 3.14159) {
cerr << "Double object parse as wrong value" << std::endl;
return TestFail;
}
- if (doubleObj.get<int32_t>(-1, &ok) != -1 || ok) {
+ if (doubleObj.get<int32_t>()) {
cerr << "Double object parse as integer" << std::endl;
return TestFail;
}
- if (doubleObj.get<uint32_t>(1, &ok) != 1 || ok) {
+ if (doubleObj.get<uint32_t>()) {
cerr << "Double object parse as unsigned integer" << std::endl;
return TestFail;
}
- if (doubleObj.get<Size>(Size(0, 0), &ok) != Size(0, 0) || ok) {
+ if (doubleObj.get<Size>()) {
cerr << "Double object parse as Size" << std::endl;
return TestFail;
}
@@ -313,27 +312,27 @@ protected:
return TestFail;
}
- if (sizeObj.get<string>("", &ok) != "" || ok) {
+ if (sizeObj.get<string>()) {
cerr << "Size object parse as string" << std::endl;
return TestFail;
}
- if (sizeObj.get<double>(1.0, &ok) != 1.0 || ok) {
+ if (sizeObj.get<double>()) {
cerr << "Size object parse as double" << std::endl;
return TestFail;
}
- if (sizeObj.get<int32_t>(-1, &ok) != -1 || ok) {
+ if (sizeObj.get<int32_t>()) {
cerr << "Size object parse as integer" << std::endl;
return TestFail;
}
- if (sizeObj.get<uint32_t>(1, &ok) != 1 || ok) {
+ if (sizeObj.get<uint32_t>()) {
cerr << "Size object parse as unsigned integer" << std::endl;
return TestFail;
}
- if (sizeObj.get<Size>(Size(0, 0), &ok) != Size(1920, 1080) || !ok) {
+ if (sizeObj.get<Size>().value_or(Size(0, 0)) != Size(1920, 1080)) {
cerr << "Size object parse as wrong value" << std::endl;
return TestFail;
}
@@ -351,27 +350,27 @@ protected:
return TestFail;
}
- if (listObj.get<string>("", &ok) != "" || ok) {
+ if (listObj.get<string>()) {
cerr << "List object parse as string" << std::endl;
return TestFail;
}
- if (listObj.get<double>(1.0, &ok) != 1.0 || ok) {
+ if (listObj.get<double>()) {
cerr << "List object parse as double" << std::endl;
return TestFail;
}
- if (listObj.get<int32_t>(-1, &ok) != -1 || ok) {
+ if (listObj.get<int32_t>()) {
cerr << "List object parse as integer" << std::endl;
return TestFail;
}
- if (listObj.get<uint32_t>(1, &ok) != 1 || ok) {
+ if (listObj.get<uint32_t>()) {
cerr << "List object parse as unsigne integer" << std::endl;
return TestFail;
}
- if (listObj.get<Size>(Size(0, 0), &ok) != Size(0, 0) || ok) {
+ if (listObj.get<Size>()) {
cerr << "String list object parse as Size" << std::endl;
return TestFail;
}
@@ -424,27 +423,27 @@ protected:
return TestFail;
}
- if (dictObj.get<string>("", &ok) != "" || ok) {
+ if (dictObj.get<string>()) {
cerr << "Dictionary object parse as string" << std::endl;
return TestFail;
}
- if (dictObj.get<double>(1.0, &ok) != 1.0 || ok) {
+ if (dictObj.get<double>()) {
cerr << "Dictionary object parse as double" << std::endl;
return TestFail;
}
- if (dictObj.get<int32_t>(-1, &ok) != -1 || ok) {
+ if (dictObj.get<int32_t>()) {
cerr << "Dictionary object parse as integer" << std::endl;
return TestFail;
}
- if (dictObj.get<uint32_t>(1, &ok) != 1 || ok) {
+ if (dictObj.get<uint32_t>()) {
cerr << "Dictionary object parse as unsigned integer" << std::endl;
return TestFail;
}
- if (dictObj.get<Size>(Size(0, 0), &ok) != Size(0, 0) || ok) {
+ if (dictObj.get<Size>()) {
cerr << "Dictionary object parse as Size" << std::endl;
return TestFail;
}
--
Regards,
Laurent Pinchart
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