From f4cbc4920f578a31e6d338e68a25455884c1d6f5 Mon Sep 17 00:00:00 2001
From: rustaceanrob <rob.netzke@gmail.com>
Date: Thu, 14 Aug 2025 10:05:12 +0100
Subject: [PATCH 1/2] Naively write every outpoint

---
 hintfile/src/bin/construct.rs | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/hintfile/src/bin/construct.rs b/hintfile/src/bin/construct.rs
index dbf7d5e..bf32faa 100644
--- a/hintfile/src/bin/construct.rs
+++ b/hintfile/src/bin/construct.rs
@@ -1,6 +1,7 @@
-use std::{fs::File, sync::Arc};
+use std::{fs::File, io::Write, sync::Arc};
 
-use bitcoin::consensus;
+use bitcoin::{consensus, OutPoint};
+use hintfile::write_compact_size;
 use kernel::{ChainType, ChainstateManager, ChainstateManagerOptions, ContextBuilder, KernelError};
 
 fn main() {
@@ -21,6 +22,8 @@ fn main() {
     let chainman = ChainstateManager::new(options, context).unwrap();
     println!("Chain state initialized");
     let genesis = chainman.get_block_index_genesis();
+    let tip = chainman.get_block_index_tip().block_hash().hash;
+    file.write_all(&tip).unwrap();
     let mut current = chainman.get_next_block_index(genesis).unwrap();
     loop {
         let block = chainman.read_block_data(&current).unwrap();
@@ -30,7 +33,25 @@ fn main() {
         println!("On block {}", current.height());
         let mut delta: u64 = 0;
         let mut block_offsets: Vec<u64> = Vec::new();
-        for tx in transactions {}
+        for tx in transactions {
+            let txid = tx.compute_txid();
+            for (index, _txout) in tx.outputs.iter().enumerate() {
+                let _outpoint = OutPoint {
+                    txid,
+                    vout: index as u32,
+                };
+                // if true
+                block_offsets.push(delta);
+                delta = 0;
+            }
+        }
+        // Overflows 32 bit machines
+        let len_encode = block_offsets.len() as u64;
+        println!("Writing block offsets");
+        write_compact_size(len_encode, &mut file).expect("unexpected EOF");
+        for offset in block_offsets {
+            write_compact_size(offset, &mut file).expect("unexpected EOF");
+        }
         match chainman.get_next_block_index(current) {
             Ok(next) => current = next,
             Err(KernelError::OutOfBounds) => break,

From 3aa7effead041dafbd90b3a1e82159a5d1adc41d Mon Sep 17 00:00:00 2001
From: rustaceanrob <rob.netzke@gmail.com>
Date: Thu, 14 Aug 2025 16:31:05 +0100
Subject: [PATCH 2/2] Make `Hints` immutable

In practice, many threads will probably be grabbing this.
---
 hintfile/src/lib.rs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/hintfile/src/lib.rs b/hintfile/src/lib.rs
index 92451ea..6015460 100644
--- a/hintfile/src/lib.rs
+++ b/hintfile/src/lib.rs
@@ -72,8 +72,11 @@ impl Hints {
     ///
     /// If there are no offset present at that height, aka an overflow, or the entry has already
     /// been fetched.
-    pub fn take_block_offsets(&mut self, height: BlockHeight) -> Vec<u64> {
-        self.map.remove(&height).expect("block height overflow")
+    pub fn get_block_offsets(&self, height: BlockHeight) -> Vec<u64> {
+        self.map
+            .get(&height)
+            .cloned()
+            .expect("block height overflow")
     }
 }