Merge pull request #251 from str4d/bundled-prover

zcash_proofs: Add LocalProver::bundled

zcash_proofs/Cargo.toml

@@ -20,6 +20,7 @@ ff = { version = "0.6", path = "../ff" }
 minreq = { version = "2", features = ["https"], optional = true }
 pairing = { version = "0.16", path = "../pairing" }
 rand_core = "0.5.1"
+wagyu-zcash-parameters = { version = "0.2", optional = true }
 zcash_primitives = { version = "0.2", path = "../zcash_primitives" }
 
 [dev-dependencies]
@@ -27,6 +28,7 @@ rand_xorshift = "0.2"
 
 [features]
 default = ["local-prover", "multicore"]
+bundled-prover = ["wagyu-zcash-parameters"]
 download-params = ["minreq"]
 local-prover = ["directories"]
 multicore = ["bellman/multicore"]

zcash_proofs/src/lib.rs

@@ -22,11 +22,13 @@ mod hashreader;
 pub mod sapling;
 pub mod sprout;
 
-#[cfg(feature = "local-prover")]
+#[cfg(any(feature = "local-prover", feature = "bundled-prover"))]
 pub mod prover;
 
 // Circuit names
+#[cfg(feature = "local-prover")]
 const SAPLING_SPEND_NAME: &str = "sapling-spend.params";
+#[cfg(feature = "local-prover")]
 const SAPLING_OUTPUT_NAME: &str = "sapling-output.params";
 
 // Circuit hashes
@@ -118,11 +120,27 @@ pub fn load_parameters(
     let sprout_fs =
         sprout_path.map(|p| File::open(p).expect("couldn't load Sprout groth16 parameters file"));
 
-    let mut spend_fs = hashreader::HashReader::new(BufReader::with_capacity(1024 * 1024, spend_fs));
+    parse_parameters(
-    let mut output_fs =
+        BufReader::with_capacity(1024 * 1024, spend_fs),
-        hashreader::HashReader::new(BufReader::with_capacity(1024 * 1024, output_fs));
+        BufReader::with_capacity(1024 * 1024, output_fs),
-    let mut sprout_fs =
+        sprout_fs.map(|fs| BufReader::with_capacity(1024 * 1024, fs)),
-        sprout_fs.map(|fs| hashreader::HashReader::new(BufReader::with_capacity(1024 * 1024, fs)));
+    )
+}
+
+fn parse_parameters<R: io::Read>(
+    spend_fs: R,
+    output_fs: R,
+    sprout_fs: Option<R>,
+) -> (
+    Parameters<Bls12>,
+    PreparedVerifyingKey<Bls12>,
+    Parameters<Bls12>,
+    PreparedVerifyingKey<Bls12>,
+    Option<PreparedVerifyingKey<Bls12>>,
+) {
+    let mut spend_fs = hashreader::HashReader::new(spend_fs);
+    let mut output_fs = hashreader::HashReader::new(output_fs);
+    let mut sprout_fs = sprout_fs.map(|fs| hashreader::HashReader::new(fs));
 
     // Deserialize params
     let spend_params = Parameters::<Bls12>::read(&mut spend_fs, false)

zcash_proofs/src/prover.rs

@@ -2,7 +2,6 @@
 
 use bellman::groth16::{Parameters, PreparedVerifyingKey};
 use pairing::bls12_381::{Bls12, Fr};
-use std::path::Path;
 use zcash_primitives::{
     jubjub::{edwards, fs::Fs, Unknown},
     primitives::{Diversifier, PaymentAddress, ProofGenerationKey},
@@ -16,10 +15,15 @@ use zcash_primitives::{
     JUBJUB,
 };
 
-use crate::{
+use crate::sapling::SaplingProvingContext;
-    default_params_folder, load_parameters, sapling::SaplingProvingContext, SAPLING_OUTPUT_NAME,
+
-    SAPLING_SPEND_NAME,
+#[cfg(feature = "local-prover")]
-};
+use crate::{default_params_folder, load_parameters, SAPLING_OUTPUT_NAME, SAPLING_SPEND_NAME};
+#[cfg(feature = "local-prover")]
+use std::path::Path;
+
+#[cfg(feature = "bundled-prover")]
+use crate::parse_parameters;
 
 /// An implementation of [`TxProver`] using Sapling Spend and Output parameters from
 /// locally-accessible paths.
@@ -48,6 +52,7 @@ impl LocalTxProver {
     ///
     /// This function will panic if the paths do not point to valid parameter files with
     /// the expected hashes.
+    #[cfg(feature = "local-prover")]
     pub fn new(spend_path: &Path, output_path: &Path) -> Self {
         let (spend_params, spend_vk, output_params, _, _) =
             load_parameters(spend_path, output_path, None);
@@ -79,6 +84,7 @@ impl LocalTxProver {
     ///
     /// This function will panic if the parameters in the default local location do not
     /// have the expected hashes.
+    #[cfg(feature = "local-prover")]
     pub fn with_default_location() -> Option<Self> {
         let params_dir = default_params_folder()?;
         let (spend_path, output_path) = if params_dir.exists() {
@@ -95,6 +101,23 @@ impl LocalTxProver {
 
         Some(LocalTxProver::new(&spend_path, &output_path))
     }
+
+    /// Creates a `LocalTxProver` using Sapling parameters bundled inside the binary.
+    ///
+    /// This requires the `bundled-prover` feature, which will increase the binary size by
+    /// around 50 MiB.
+    #[cfg(feature = "bundled-prover")]
+    pub fn bundled() -> Self {
+        let (spend_buf, output_buf) = wagyu_zcash_parameters::load_sapling_parameters();
+        let (spend_params, spend_vk, output_params, _, _) =
+            parse_parameters(&spend_buf[..], &output_buf[..], None);
+
+        LocalTxProver {
+            spend_params,
+            spend_vk,
+            output_params,
+        }
+    }
 }
 
 impl TxProver for LocalTxProver {