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`SHAMap::walkMap` and `walkMapParallel` treat a null `descendNoStore` result as "this node is missing" and record it in their `missingNodes` output, but `descendNoStore` used the throwing `fetchNode`, so that branch could never run for a backed map. `Ledger::walkLedger` propagated the throw instead of returning false, its "N missing account node(s)" log never printed, and `LedgerCleaner` never reached the path that clears the ledger and re-acquires it. `descendNoStore` now uses `fetchNodeNT`, which makes all three behave as written, and the null check after `fetchNode` in `descend` goes away as the dead code it always was. `visitNodes` and `visitLeaves` now return whether the walk read every node it reached, and the walk ends at the first node it cannot read, since no caller can use a partial result. `SHAMapStoreImp::run` abandons the rotation cycle on false, which is what its former `catch (SHAMapMissingNode)` did and what `clearPrior` plus the archive deletion in `rotate` require. `processReplayDeltaRequest` answers `reNO_NODE`, the code `xrpl.proto` documents for nodes we do not have, rather than sending a transaction list it knows is short, and clears the header it had already set so an error reply carries no partial payload. The two `RCLConsensus` walks run on unbacked maps, which have no node store to fail to read, so they cannot report an incomplete result. `walkMapParallel` decided its result from the exceptions its workers caught, yet those workers record an unreadable child in `missingNodes` instead, so it never consulted the list it was filling. The result now counts what this call recorded, measured against the caller's initial vector size. The pass that reads the root's children runs before any worker and dropped a null child silently, because the loop that spawns workers skips one; it records the miss itself now. A one-node map reports complete, which is what `walkMap` already reported for the same input, and the worker handler catches `std::exception` so that nothing leaves a worker's thread. The workers share one missing-node budget, so the critical section tests it before it adds to the list and not only after, which keeps the total within the cap the caller asked for. Eleven gtests in `src/tests/libxrpl/shamap/SHAMapMissingNode.cpp` cover the three walks over a partially copied map, the missing-node budget both within one walk and across the workers, an empty branch of the root, an early stop by the visitor, a stop at the root, a map holding only its root, and a map whose root is a leaf. A case in `src/test/app/LedgerReplay_test.cpp` asks for a replay delta on a ledger whose transaction map holds nothing below its root, and checks the error reply.
The XRP Ledger
The XRP Ledger is a decentralized cryptographic ledger powered by a network of peer-to-peer nodes. The XRP Ledger uses a novel Byzantine Fault Tolerant consensus algorithm to settle and record transactions in a secure distributed database without a central operator.
XRP
XRP is a public, counterparty-free crypto-asset native to the XRP Ledger, and is designed as a gas token for network services and to bridge different currencies. XRP is traded on the open-market and is available for anyone to access. The XRP Ledger was created in 2012 with a finite supply of 100 billion units of XRP.
xrpld
The server software that powers the XRP Ledger is called xrpld and is available in this repository under the permissive ISC open-source license. The xrpld server software is written primarily in C++ and runs on a variety of platforms. The xrpld server software can run in several modes depending on its configuration.
If you are interested in running an API Server (including a Full History Server), take a look at Clio. (xrpld Reporting Mode has been replaced by Clio.)
Build from Source
- Read the build instructions in
BUILD.md - If you encounter any issues, please open an issue
Key Features of the XRP Ledger
- Censorship-Resistant Transaction Processing: No single party decides which transactions succeed or fail, and no one can "roll back" a transaction after it completes. As long as those who choose to participate in the network keep it healthy, they can settle transactions in seconds.
- Fast, Efficient Consensus Algorithm: The XRP Ledger's consensus algorithm settles transactions in 4 to 5 seconds, processing at a throughput of up to 1500 transactions per second. These properties put XRP at least an order of magnitude ahead of other top digital assets.
- Finite XRP Supply: When the XRP Ledger began, 100 billion XRP were created, and no more XRP will ever be created. The available supply of XRP decreases slowly over time as small amounts are destroyed to pay transaction fees.
- Responsible Software Governance: A team of full-time developers at Ripple & other organizations maintain and continually improve the XRP Ledger's underlying software with contributions from the open-source community. Ripple acts as a steward for the technology and an advocate for its interests.
- Secure, Adaptable Cryptography: The XRP Ledger relies on industry standard digital signature systems like ECDSA (the same scheme used by Bitcoin) but also supports modern, efficient algorithms like Ed25519. The extensible nature of the XRP Ledger's software makes it possible to add and disable algorithms as the state of the art in cryptography advances.
- Modern Features: Features like Escrow, Checks, and Payment Channels support financial applications atop of the XRP Ledger. This toolbox of advanced features comes with safety features like a process for amending the network and separate checks against invariant constraints.
- On-Ledger Decentralized Exchange: In addition to all the features that make XRP useful on its own, the XRP Ledger also has a fully-functional accounting system for tracking and trading obligations denominated in any way users want, and an exchange built into the protocol. The XRP Ledger can settle long, cross-currency payment paths and exchanges of multiple currencies in atomic transactions, bridging gaps of trust with XRP.
Source Code
Here are some good places to start learning the source code:
- Read the markdown files in the source tree:
src/xrpld/**/*.md. - Read the levelization document to get an idea of the internal dependency graph.
- In the big picture, the
mainfunction constructs anApplicationImpobject, which implements theApplicationvirtual interface. Almost every component in the application takes anApplication¶meter in its constructor, typically namedappand stored as a member variableapp_. This allows most components to depend on any other component.
Repository Contents
| Folder | Contents |
|---|---|
./bin |
Scripts and data files for XRPL developers. |
./Builds |
Platform-specific guides for building xrpld. |
./docs |
Source documentation files and doxygen config. |
./cfg |
Example configuration files. |
./src |
Source code. |
./crates |
Rust source code. |
Some of the directories under src are external repositories included using
git-subtree. See those directories' README files for more details.