token-metadata: Implement example program (#4546)

* token-metadata: Add example program

* Implement UpdateField

* Implement RemoveKey

* Implement UpdateAuthority

* Implement Emit

* Move serialize helper to TLV

* Add CI job

* Remove re-export

* Fix merge error

Author: joncinque

.github/workflows/pull-request-token-metadata.yml

@@ -0,0 +1,62 @@
+name: Token-Metadata Pull Request
+
+on:
+  pull_request:
+    paths:
+    - 'token-metadata/**'
+    - 'token/program-2022/**'
+    - 'ci/*-version.sh'
+    - '.github/workflows/pull-request-token-metadata.yml'
+  push:
+    branches: [master]
+    paths:
+    - 'token-metadata/**'
+    - 'token/program-2022/**'
+    - 'ci/*-version.sh'
+    - '.github/workflows/pull-request-token-metadata.yml'
+
+jobs:
+  cargo-test-sbf:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Set env vars
+        run: |
+          source ci/rust-version.sh
+          echo "RUST_STABLE=$rust_stable" >> $GITHUB_ENV
+          source ci/solana-version.sh
+          echo "SOLANA_VERSION=$solana_version" >> $GITHUB_ENV
+
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: ${{ env.RUST_STABLE }}
+          override: true
+          profile: minimal
+
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+          key: cargo-build-${{ hashFiles('**/Cargo.lock') }}-${{ env.RUST_STABLE}}
+
+      - uses: actions/cache@v2
+        with:
+          path: |
+            ~/.cargo/bin/rustfilt
+          key: cargo-sbf-bins-${{ runner.os }}
+
+      - uses: actions/cache@v2
+        with:
+          path: ~/.cache/solana
+          key: solana-${{ env.SOLANA_VERSION }}
+
+      - name: Install dependencies
+        run: |
+          ./ci/install-build-deps.sh
+          ./ci/install-program-deps.sh
+          echo "$HOME/.local/share/solana/install/active_release/bin" >> $GITHUB_PATH
+
+      - name: Build and test example
+        run: ./ci/cargo-test-sbf.sh token-metadata/example

Cargo.lock

@@ -40,6 +40,7 @@ members = [
   "stateless-asks/program",
   "token-lending/cli",
   "token-lending/program",
+  "token-metadata/example",
   "token-metadata/interface",
   "token-swap/program",
   "token-swap/program/fuzz",

Cargo.toml

@@ -408,6 +408,54 @@ impl<'a> TlvState for TlvStateMut<'a> {
     }
 }
 
+/// Packs a borsh-serializable value into an existing TLV space, reallocating
+/// the account and TLV as needed to accommodate for any change in space
+#[cfg(feature = "borsh")]
+pub fn realloc_and_borsh_serialize<V: SplDiscriminate + borsh::BorshSerialize>(
+    account_info: &solana_program::account_info::AccountInfo,
+    value: &V,
+) -> Result<(), ProgramError> {
+    let previous_length = {
+        let data = account_info.try_borrow_data()?;
+        let TlvIndices {
+            type_start: _,
+            length_start,
+            value_start,
+        } = get_indices(&data, V::SPL_DISCRIMINATOR, false)?;
+        usize::try_from(*pod_from_bytes::<Length>(&data[length_start..value_start])?)?
+    };
+    let new_length = solana_program::borsh::get_instance_packed_len(&value)?;
+    let previous_account_size = account_info.try_data_len()?;
+    if previous_length < new_length {
+        // size increased, so realloc the account, then the TLV entry, then write data
+        let additional_bytes = new_length
+            .checked_sub(previous_length)
+            .ok_or(ProgramError::AccountDataTooSmall)?;
+        account_info.realloc(previous_account_size.saturating_add(additional_bytes), true)?;
+        let mut buffer = account_info.try_borrow_mut_data()?;
+        let mut state = TlvStateMut::unpack(&mut buffer)?;
+        state.realloc::<V>(new_length)?;
+        state.borsh_serialize(value)?;
+    } else {
+        // do it backwards otherwise, write the state, realloc TLV, then the account
+        let mut buffer = account_info.try_borrow_mut_data()?;
+        let mut state = TlvStateMut::unpack(&mut buffer)?;
+        state.borsh_serialize(value)?;
+        let removed_bytes = previous_length
+            .checked_sub(new_length)
+            .ok_or(ProgramError::AccountDataTooSmall)?;
+        if removed_bytes > 0 {
+            // we decreased the size, so need to realloc the TLV, then the account
+            state.realloc::<V>(new_length)?;
+            // this is probably fine, but be safe and avoid invalidating references
+            drop(state);
+            drop(buffer);
+            account_info.realloc(previous_account_size.saturating_sub(removed_bytes), false)?;
+        }
+    }
+    Ok(())
+}
+
 /// Get the base size required for TLV data
 const fn get_base_len() -> usize {
     let indices = get_indices_unchecked(0);

libraries/type-length-value/src/state.rs

@@ -0,0 +1,30 @@
+[package]
+name = "spl-token-metadata-example"
+version = "0.1.0"
+description = "Solana Program Library Token Metadata Example Program"
+authors = ["Solana Labs Maintainers <[email protected]>"]
+repository = "https://github.com/solana-labs/solana-program-library"
+license = "Apache-2.0"
+edition = "2021"
+
+[features]
+no-entrypoint = []
+test-sbf = []
+
+[dependencies]
+solana-program = "1.14.12"
+spl-type-length-value = { version = "0.1.0" , path = "../../libraries/type-length-value" }
+spl-token-2022 = { version = "0.6.0", path = "../../token/program-2022" }
+spl-token-metadata-interface = { version = "0.1.0", path = "../interface" }
+
+[dev-dependencies]
+solana-program-test = "1.14.12"
+solana-sdk = "1.14.12"
+spl-token-client = { version = "0.5", path = "../../token/client" }
+test-case = "3.1"
+
+[lib]
+crate-type = ["cdylib", "lib"]
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]

token-metadata/example/Cargo.toml

@@ -0,0 +1,24 @@
+//! Program entrypoint
+
+use {
+    crate::processor,
+    solana_program::{
+        account_info::AccountInfo, entrypoint, entrypoint::ProgramResult,
+        program_error::PrintProgramError, pubkey::Pubkey,
+    },
+    spl_token_metadata_interface::error::TokenMetadataError,
+};
+
+entrypoint!(process_instruction);
+fn process_instruction(
+    program_id: &Pubkey,
+    accounts: &[AccountInfo],
+    instruction_data: &[u8],
+) -> ProgramResult {
+    if let Err(error) = processor::process(program_id, accounts, instruction_data) {
+        // catch the error so we can print it
+        error.print::<TokenMetadataError>();
+        return Err(error);
+    }
+    Ok(())
+}

token-metadata/example/src/entrypoint.rs

@@ -0,0 +1,10 @@
+//! Crate defining an example program for storing SPL token metadata
+
+#![allow(clippy::integer_arithmetic)]
+#![deny(missing_docs)]
+#![cfg_attr(not(test), forbid(unsafe_code))]
+
+pub mod processor;
+
+#[cfg(not(feature = "no-entrypoint"))]
+mod entrypoint;