From d70ec9bf447f7a46e347c3bc5ad58fd88aff46a2 Mon Sep 17 00:00:00 2001
From: jacqueline <me@jacqueline.id.au>
Date: Tue, 21 Nov 2023 13:49:47 +1100
Subject: Add lua functions to get database content

---
 src/database/database.cpp | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

(limited to 'src/database/database.cpp')

diff --git a/src/database/database.cpp b/src/database/database.cpp
index 142735d8..0967eb95 100644
--- a/src/database/database.cpp
+++ b/src/database/database.cpp
@@ -857,4 +857,48 @@ auto IndexRecord::Expand(std::size_t page_size) const
   };
 }
 
+Iterator::Iterator(std::weak_ptr<Database> db, const IndexInfo& idx)
+    : db_(db), prev_pos_(), current_pos_() {
+  std::string prefix = EncodeIndexPrefix(
+      IndexKey::Header{.id = idx.id, .depth = 0, .components_hash = 0});
+  current_pos_ = Continuation{.prefix = {prefix.data(), prefix.size()},
+                              .start_key = {prefix.data(), prefix.size()},
+                              .forward = true,
+                              .was_prev_forward = true,
+                              .page_size = 1};
+}
+
+Iterator::Iterator(std::weak_ptr<Database> db, const Continuation& c)
+    : db_(db), prev_pos_(), current_pos_(c) {}
+
+auto Iterator::Prev() -> std::optional<IndexRecord> {
+  if (!prev_pos_) {
+    return {};
+  }
+  auto db = db_.lock();
+  if (!db) {
+    return {};
+  }
+  std::unique_ptr<Result<IndexRecord>> res{
+      db->GetPage<IndexRecord>(&*prev_pos_).get()};
+  prev_pos_ = res->prev_page();
+  current_pos_ = prev_pos_;
+  return *res->values()[0];
+}
+
+auto Iterator::Next() -> std::optional<IndexRecord> {
+  if (!current_pos_) {
+    return {};
+  }
+  auto db = db_.lock();
+  if (!db) {
+    return {};
+  }
+  std::unique_ptr<Result<IndexRecord>> res{
+      db->GetPage<IndexRecord>(&*current_pos_).get()};
+  prev_pos_ = current_pos_;
+  current_pos_ = res->next_page();
+  return *res->values()[0];
+}
+
 }  // namespace database
-- 
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