From 63c15c9803c36973cb8b1320b2ab5c76c8d2466e Mon Sep 17 00:00:00 2001
From: Sergei Pepyakin <sergei@parity.io>
Date: Sun, 1 Sep 2019 02:19:31 +0200
Subject: [PATCH] Minimum balance (#3519)
---
substrate/srml/contracts/src/exec.rs | 7 +++
substrate/srml/contracts/src/wasm/mod.rs | 66 ++++++++++++++++++++
substrate/srml/contracts/src/wasm/runtime.rs | 10 +++
3 files changed, 83 insertions(+)
diff --git a/substrate/srml/contracts/src/exec.rs b/substrate/srml/contracts/src/exec.rs
index 818a689f99d..586ee3746b8 100644
--- a/substrate/srml/contracts/src/exec.rs
+++ b/substrate/srml/contracts/src/exec.rs
@@ -154,6 +154,9 @@ pub trait Ext {
/// Returns a reference to the timestamp of the current block
fn now(&self) -> &MomentOf<Self::T>;
+ /// Returns the minimum balance that is required for creating an account.
+ fn minimum_balance(&self) -> BalanceOf<Self::T>;
+
/// Returns a random number for the current block with the given subject.
fn random(&self, subject: &[u8]) -> SeedOf<Self::T>;
@@ -766,6 +769,10 @@ where
&self.timestamp
}
+ fn minimum_balance(&self) -> BalanceOf<T> {
+ self.ctx.config.existential_deposit
+ }
+
fn deposit_event(&mut self, topics: Vec<T::Hash>, data: Vec<u8>) {
self.ctx.deferred.push(DeferredAction::DepositEvent {
topics,
diff --git a/substrate/srml/contracts/src/wasm/mod.rs b/substrate/srml/contracts/src/wasm/mod.rs
index 99578fee274..c623313824b 100644
--- a/substrate/srml/contracts/src/wasm/mod.rs
+++ b/substrate/srml/contracts/src/wasm/mod.rs
@@ -282,6 +282,10 @@ mod tests {
&1111
}
+ fn minimum_balance(&self) -> u64 {
+ 666
+ }
+
fn random(&self, subject: &[u8]) -> H256 {
H256::from_slice(subject)
}
@@ -364,6 +368,9 @@ mod tests {
fn now(&self) -> &u64 {
(**self).now()
}
+ fn minimum_balance(&self) -> u64 {
+ (**self).minimum_balance()
+ }
fn random(&self, subject: &[u8]) -> H256 {
(**self).random(subject)
}
@@ -1176,6 +1183,65 @@ mod tests {
).unwrap();
}
+ const CODE_MINIMUM_BALANCE: &str = r#"
+(module
+ (import "env" "ext_minimum_balance" (func $ext_minimum_balance))
+ (import "env" "ext_scratch_size" (func $ext_scratch_size (result i32)))
+ (import "env" "ext_scratch_read" (func $ext_scratch_read (param i32 i32 i32)))
+ (import "env" "memory" (memory 1 1))
+
+ (func $assert (param i32)
+ (block $ok
+ (br_if $ok
+ (get_local 0)
+ )
+ (unreachable)
+ )
+ )
+
+ (func (export "call")
+ (call $ext_minimum_balance)
+
+ ;; assert $ext_scratch_size == 8
+ (call $assert
+ (i32.eq
+ (call $ext_scratch_size)
+ (i32.const 8)
+ )
+ )
+
+ ;; copy contents of the scratch buffer into the contract's memory.
+ (call $ext_scratch_read
+ (i32.const 8) ;; Pointer in memory to the place where to copy.
+ (i32.const 0) ;; Offset from the start of the scratch buffer.
+ (i32.const 8) ;; Count of bytes to copy.
+ )
+
+ ;; assert that contents of the buffer is equal to the i64 value of 666.
+ (call $assert
+ (i64.eq
+ (i64.load
+ (i32.const 8)
+ )
+ (i64.const 666)
+ )
+ )
+ )
+ (func (export "deploy"))
+)
+"#;
+
+ #[test]
+ fn minimum_balance() {
+ let mut gas_meter = GasMeter::with_limit(50_000, 1);
+ let _ = execute(
+ CODE_MINIMUM_BALANCE,
+ vec![],
+ MockExt::default(),
+ &mut gas_meter,
+ ).unwrap();
+ }
+
const CODE_RANDOM: &str = r#"
(module
(import "env" "ext_random" (func $ext_random (param i32 i32)))
diff --git a/substrate/srml/contracts/src/wasm/runtime.rs b/substrate/srml/contracts/src/wasm/runtime.rs
index c6ef1bb3f56..4baece3d918 100644
--- a/substrate/srml/contracts/src/wasm/runtime.rs
+++ b/substrate/srml/contracts/src/wasm/runtime.rs
@@ -611,6 +611,16 @@ define_env!(Env, <E: Ext>,
Ok(())
},
+ // Stores the minimum balance (a.k.a. existential deposit) into the scratch buffer.
+ //
+ // The data is encoded as T::Balance. The current contents of the scratch buffer are
+ // overwritten.
+ ext_minimum_balance(ctx) => {
+ ctx.scratch_buf.clear();
+ ctx.ext.minimum_balance().encode_to(&mut ctx.scratch_buf);
+ Ok(())
+ },
+
// Decodes the given buffer as a `T::Call` and adds it to the list
// of to-be-dispatched calls.
//
--
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