add empty / error header constructor, put u32::MAX as size for compac…

core/src/data_lookup/compact.rs

@@ -55,6 +55,13 @@ impl CompactDataLookup {
 
 impl From<DataLookup> for CompactDataLookup {
 	fn from(lookup: DataLookup) -> Self {
-		CompactDataLookup::from_expanded(&lookup)
+		if lookup.is_error {
+			CompactDataLookup {
+				size: u32::MAX,
+				index: Vec::default(),
+			}
+		} else {
+			CompactDataLookup::from_expanded(&lookup)
+		}
 	}
 }

core/src/data_lookup/mod.rs

@@ -33,6 +33,7 @@ pub enum Error {
 )]
 pub struct DataLookup {
 	pub(crate) index: Vec<(AppId, DataLookupRange)>,
+	pub(crate) is_error: bool,
 }
 
 impl DataLookup {
@@ -112,12 +113,25 @@ impl DataLookup {
 			})
 			.collect::<Result<_, _>>()?;
 
-		Ok(Self { index })
+		Ok(Self {
+			index,
+			is_error: false,
+		})
 	}
 
 	/// This function is only used when something has gone wrong during header extension building
 	pub fn new_empty() -> Self {
-		Self { index: Vec::new() }
+		Self {
+			index: Vec::new(),
+			is_error: false,
+		}
+	}
+
+	pub fn new_error() -> Self {
+		Self {
+			index: Vec::new(),
+			is_error: true,
+		}
 	}
 }
 
@@ -146,7 +160,10 @@ impl TryFrom<CompactDataLookup> for DataLookup {
 			index.push((prev_id, offset..compacted.size));
 		}
 
-		let lookup = DataLookup { index };
+		let lookup = DataLookup {
+			index,
+			is_error: false,
+		};
 		ensure!(lookup.len() == compacted.size, Error::DataNotSorted);
 
 		Ok(lookup)

core/src/header/extension/mod.rs

@@ -16,7 +16,7 @@
 #[cfg_attr(feature = "runtime", derive(PassByCodec))]
 #[repr(u8)]
 pub enum HeaderExtension {
 	V3(v3::HeaderExtension) = 2,
 }
 
 /// It forwards the call to the inner version of the header. Any invalid version will return the
@@ -52,6 +52,14 @@
 		forward_to_version!(self, cols)
 	}
 
+	pub fn get_empty_header(&self, data_root: H256) -> HeaderExtension {
+		forward_to_version!(self, get_empty_header, data_root).into()
+	}
+
+	pub fn get_faulty_header(&self, data_root: H256) -> HeaderExtension {
+		forward_to_version!(self, get_faulty_header, data_root).into()
+	}
+
 	pub fn get_header_version(&self) -> HeaderVersion {
 		match self {
 			HeaderExtension::V3(_) => HeaderVersion::V3,

core/src/header/extension/v3.rs

@@ -30,4 +30,24 @@ impl HeaderExtension {
 	pub fn cols(&self) -> u16 {
 		self.commitment.cols
 	}
+
+	pub fn get_empty_header(&self, data_root: H256) -> Self {
+		let empty_commitment: Vec<u8> = vec![];
+		let empty_app_lookup = DataLookup::new_empty();
+		let commitment = KateCommitment::new(0, 0, data_root, empty_commitment);
+		HeaderExtension {
+			app_lookup: empty_app_lookup,
+			commitment,
+		}
+	}
+
+	pub fn get_faulty_header(&self, data_root: H256) -> Self {
+		let empty_commitment: Vec<u8> = vec![];
+		let error_app_lookup = DataLookup::new_error();
+		let commitment = KateCommitment::new(0, 0, data_root, empty_commitment);
+		HeaderExtension {
+			app_lookup: error_app_lookup,
+			commitment,
+		}
+	}
 }