Struct MerkleTree 

pub struct MerkleTree { /* private fields */ }

Merkle tree for airdrop campaign

Construction Rules (aligned with miracle-copy and escrow-copy):

1. Single leaf case: Duplicate the leaf before building tree
   • Root = hash(leaf, leaf) instead of root = leaf
2. Odd nodes at level: Hash last node with itself
   • Ensures consistent tree structure
3. Deterministic: Same allocations always produce same root

Implementations

impl MerkleTree

pub fn new(allocations: Vec<AirdropAllocation>) -> Result<Self, String>

Create a new merkle tree from airdrop allocations

Parameters

• allocations: Vector of (recipient, amount) allocations

Returns

• Ok(MerkleTree) if successful
• Err(String) if allocations is empty

Single Leaf Handling

If only one allocation exists, the leaf is duplicated before building the tree. This matches miracle-copy and escrow-copy’s approach for consistency.

Example

use airdrop_api::merkle::{MerkleTree, AirdropAllocation};
use solana_program::pubkey::Pubkey;

let allocations = vec![
    AirdropAllocation::new(Pubkey::new_unique(), 1000),
    AirdropAllocation::new(Pubkey::new_unique(), 2000),
];

let tree = MerkleTree::new(allocations)?;
println!("Merkle root: {:?}", tree.root());

pub fn root(&self) -> [u8; 32]

Get the merkle root hash

pub fn generate_proof( &self, allocation_index: usize, ) -> Result<MerkleProof, String>

Generate a merkle proof for a specific allocation

Parameters

• allocation_index: Index of the allocation in the original data

Returns

• Ok(MerkleProof) if successful
• Err(String) if index is out of bounds

Example

let tree = MerkleTree::new(allocations)?;
let proof = tree.generate_proof(0)?;

pub fn find_and_generate_proof( &self, recipient: &Pubkey, ) -> Option<Result<MerkleProof, String>>

Find and generate proof for a specific recipient

Parameters

• recipient: Recipient wallet address

Returns

• Some(Ok(MerkleProof)) if recipient found
• Some(Err(String)) if found but proof generation failed
• None if recipient not found

pub fn allocation_count(&self) -> usize

Get the number of allocations in the tree

pub fn get_allocation(&self, index: usize) -> Option<&AirdropAllocation>

Get allocation data by index

pub fn allocations(&self) -> &[AirdropAllocation]

Get all allocation data

Trait Implementations

impl Clone for MerkleTree

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for MerkleTree

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.