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refactor(queries): extract shared bucket-pagination helper for get_ca… #717

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110 changes: 56 additions & 54 deletions src/queries.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -89,45 +89,59 @@ pub(crate) fn list_active_campaigns(
(campaigns, next_cursor)
}

pub(crate) fn get_campaigns_by_category(
/// Shared bucket-pagination helper used by both `get_campaigns_by_category`
/// and `get_creator_campaigns`. The two query functions differ only in how
/// they derive the total count and how they load a bucket — this helper
/// captures the identical traversal algorithm so there is one canonical
/// implementation.
///
/// Algorithm overview:
/// 1. Jump to the bucket containing `offset`.
/// 2. Walk entries within that bucket starting at the requested position.
/// 3. Collect up to `limit` campaigns (capped at `LIST_MAX_LIMIT`).
/// 4. When the bucket is exhausted, advance `position` past the bucket
/// boundary and repeat from step 1 with the next bucket.
fn paginate_bucketed_campaigns<F>(
env: &Env,
category: Category,
total: u32,
offset: u32,
limit: u32,
) -> soroban_sdk::Vec<Campaign> {
bucket_size: u32,
get_bucket: F,
) -> soroban_sdk::Vec<Campaign>
where
F: Fn(u32) -> soroban_sdk::Vec<u32>,
{
let capped_limit = limit.min(crate::LIST_MAX_LIMIT);
let mut campaigns = soroban_sdk::Vec::new(env);
if limit == 0 {
return campaigns;
}

let total = get_category_campaign_count(env, category);
if offset >= total {
if offset >= total || capped_limit == 0 {
return campaigns;
}

let capped_limit = limit.min(crate::LIST_MAX_LIMIT);
let end = offset.saturating_add(capped_limit).min(total);

let mut position = offset;

while position < end {
let bucket_idx = position / CATEGORY_CAMPAIGNS_BUCKET_SIZE;
let bucket = get_category_campaign_bucket(env, category, bucket_idx);
let bucket_start = bucket_idx * CATEGORY_CAMPAIGNS_BUCKET_SIZE;
let bucket_idx = position / bucket_size;
let bucket = get_bucket(bucket_idx);
let bucket_start = bucket_idx * bucket_size;
let mut idx_in_bucket = position - bucket_start;

let bucket_len = bucket.len();
while idx_in_bucket < bucket_len && position < end {
let campaign_id = bucket.get(idx_in_bucket).unwrap();
if let Some(campaign) = get_campaign(env, campaign_id) {
campaigns.push_back(campaign);
if let Some(campaign_id) = bucket.get(idx_in_bucket) {
if let Some(campaign) = get_campaign(env, campaign_id) {
campaigns.push_back(campaign);
}
}
idx_in_bucket += 1;
position += 1;
}

if idx_in_bucket >= bucket_len {
position = if bucket_len == 0 {
bucket_start + CATEGORY_CAMPAIGNS_BUCKET_SIZE
bucket_start + bucket_size
} else {
bucket_start + bucket_len
};
Expand All @@ -137,6 +151,23 @@ pub(crate) fn get_campaigns_by_category(
campaigns
}

pub(crate) fn get_campaigns_by_category(
env: &Env,
category: Category,
offset: u32,
limit: u32,
) -> soroban_sdk::Vec<Campaign> {
let total = get_category_campaign_count(env, category);
paginate_bucketed_campaigns(
env,
total,
offset,
limit,
CATEGORY_CAMPAIGNS_BUCKET_SIZE,
|bucket_idx| get_category_campaign_bucket(env, category, bucket_idx),
)
}

/// #534: jumps straight to the bucket containing `start` instead of reading
/// every preceding bucket just to advance a counter, so paginating deep into
/// a creator with many campaigns no longer costs one ledger read per skipped
Expand All @@ -147,44 +178,15 @@ pub(crate) fn get_creator_campaigns(
start: u32,
limit: u32,
) -> soroban_sdk::Vec<Campaign> {
let capped_limit = limit.min(crate::LIST_MAX_LIMIT);
let total = get_creator_campaign_count(env, &creator);
let mut campaigns = soroban_sdk::Vec::new(env);

if start >= total || capped_limit == 0 {
return campaigns;
}

let end = (start + capped_limit).min(total);
let mut position = start;

while position < end {
let bucket_idx = position / CREATOR_CAMPAIGNS_BUCKET_SIZE;
let bucket = get_creator_campaign_bucket(env, &creator, bucket_idx);
let bucket_start = bucket_idx * CREATOR_CAMPAIGNS_BUCKET_SIZE;
let mut idx_in_bucket = position - bucket_start;

let bucket_len = bucket.len();
while idx_in_bucket < bucket_len && position < end {
if let Some(campaign_id) = bucket.get(idx_in_bucket) {
if let Some(campaign) = get_campaign(env, campaign_id) {
campaigns.push_back(campaign);
}
}
idx_in_bucket += 1;
position += 1;
}

if idx_in_bucket >= bucket_len {
position = if bucket_len == 0 {
bucket_start + CREATOR_CAMPAIGNS_BUCKET_SIZE
} else {
bucket_start + bucket_len
};
}
}

campaigns
paginate_bucketed_campaigns(
env,
total,
start,
limit,
CREATOR_CAMPAIGNS_BUCKET_SIZE,
|bucket_idx| get_creator_campaign_bucket(env, &creator, bucket_idx),
)
}

/// Aggregates total raised, active campaign count, and total contributors
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