config/Block: add method GetDuration()

src/config/Block.cxx

@@ -46,6 +46,18 @@ BlockParam::GetBoolValue() const
 	return With(ParseBool);
 }
 
+std::chrono::steady_clock::duration
+BlockParam::GetDuration(std::chrono::steady_clock::duration min_value) const
+{
+	return With([min_value](const char *s){
+		auto duration = ParseDuration(s);
+		if (duration < min_value)
+			throw std::invalid_argument{"Value is too small"};
+
+		return duration;
+	});
+}
+
 const BlockParam *
 ConfigBlock::GetBlockParam(const char *name) const noexcept
 {
@@ -128,6 +140,18 @@ ConfigBlock::GetBlockValue(const char *name, bool default_value) const
 	return bp->GetBoolValue();
 }
 
+std::chrono::steady_clock::duration
+ConfigBlock::GetDuration(const char *name,
+			 std::chrono::steady_clock::duration min_value,
+			 std::chrono::steady_clock::duration default_value) const
+{
+	const BlockParam *bp = GetBlockParam(name);
+	if (bp == nullptr)
+		return default_value;
+
+	return bp->GetDuration(min_value);
+}
+
 void
 ConfigBlock::ThrowWithNested() const
 {

src/config/Block.hxx

@@ -4,6 +4,7 @@
 #pragma once
 
 #include <concepts>
+#include <chrono>
 #include <string>
 #include <vector>
 
@@ -33,6 +34,9 @@ struct BlockParam {
 
 	bool GetBoolValue() const;
 
+	std::chrono::steady_clock::duration
+	GetDuration(std::chrono::steady_clock::duration min_value) const;
+
 	/**
 	 * Call this method in a "catch" block to throw a nested
 	 * exception showing the location of this setting in the
@@ -122,6 +126,11 @@ struct ConfigBlock {
 
 	bool GetBlockValue(const char *name, bool default_value) const;
 
+	std::chrono::steady_clock::duration
+	GetDuration(const char *name,
+		    std::chrono::steady_clock::duration min_value,
+		    std::chrono::steady_clock::duration default_value) const;
+
 	/**
 	 * Call this method in a "catch" block to throw a nested
 	 * exception showing the location of this block in the