From 4c6d1dd4bd55e7ee8ad697d008d3292fbf09f99e Mon Sep 17 00:00:00 2001
From: jaspervdm <j@sper.dev>
Date: Wed, 7 Oct 2020 14:09:27 +0200
Subject: [PATCH] Define get_data_from_file function on ReadablePMMR trait
 (#3464)

---
 core/src/core/pmmr/pmmr.rs          | 11 +++++++++++
 core/src/core/pmmr/readonly_pmmr.rs |  8 ++++++++
 2 files changed, 19 insertions(+)

diff --git a/core/src/core/pmmr/pmmr.rs b/core/src/core/pmmr/pmmr.rs
index 86a37bbdf..1e8cb199a 100644
--- a/core/src/core/pmmr/pmmr.rs
+++ b/core/src/core/pmmr/pmmr.rs
@@ -40,6 +40,9 @@ pub trait ReadablePMMR {
 	/// Get the hash from the underlying MMR file (ignores the remove log).
 	fn get_from_file(&self, pos: u64) -> Option<Hash>;
 
+	/// Get the data element at provided position in the MMR (ignores the remove log).
+	fn get_data_from_file(&self, pos: u64) -> Option<Self::Item>;
+
 	/// Total size of the tree, including intermediary nodes and ignoring any pruning.
 	fn unpruned_size(&self) -> u64;
 
@@ -412,6 +415,14 @@ where
 		}
 	}
 
+	fn get_data_from_file(&self, pos: u64) -> Option<Self::Item> {
+		if pos > self.last_pos {
+			None
+		} else {
+			self.backend.get_data_from_file(pos)
+		}
+	}
+
 	fn unpruned_size(&self) -> u64 {
 		self.last_pos
 	}
diff --git a/core/src/core/pmmr/readonly_pmmr.rs b/core/src/core/pmmr/readonly_pmmr.rs
index bc2f0752e..536c6736d 100644
--- a/core/src/core/pmmr/readonly_pmmr.rs
+++ b/core/src/core/pmmr/readonly_pmmr.rs
@@ -148,6 +148,14 @@ where
 		}
 	}
 
+	fn get_data_from_file(&self, pos: u64) -> Option<Self::Item> {
+		if pos > self.last_pos {
+			None
+		} else {
+			self.backend.get_data_from_file(pos)
+		}
+	}
+
 	fn unpruned_size(&self) -> u64 {
 		self.last_pos
 	}