Price oracle.

language/move-lang/src/expansion/translate.rs

@@ -238,7 +238,6 @@ fn module_(
         name: name.clone(),
     };
     let current_module = ModuleIdent(sp(name_loc, mident_));
-    let is_source_module = is_source_module && !fake_natives::is_fake_native(&current_module);
     let self_aliases = module_self_aliases(&current_module);
     context.set_and_shadow_aliases(self_aliases);
     let alias_map = aliases(context, uses);

language/move-vm/natives/Cargo.toml

@@ -25,6 +25,8 @@ move-core-types = { path = "../../move-core/types", version = "0.1.0" }
 move-vm-types = { path = "../types", version = "0.1.0" }
 vm = { path = "../../vm", version = "0.1.0" }
 
+byteorder = "1.3.4"
+
 [features]
 default = []
 debug_module = []

language/move-vm/natives/src/lib.rs

@@ -9,3 +9,4 @@ pub mod event;
 pub mod hash;
 pub mod lcs;
 pub mod signature;
+pub mod oracle;

language/move-vm/natives/src/mod.rs

@@ -9,3 +9,4 @@ pub mod event;
 pub mod hash;
 pub mod lcs;
 pub mod signature;
+pub mod oracle;

language/move-vm/natives/src/oracle.rs

@@ -0,0 +1,73 @@
+use move_vm_types::natives::function::{NativeContext, NativeResult};
+use move_vm_types::loaded_data::runtime_types::Type;
+use move_vm_types::values::Value;
+use libra_types::access_path::AccessPath;
+use libra_types::account_address::AccountAddress;
+use libra_types::vm_error::{VMStatus, StatusCode};
+use libra_crypto::hash::{DefaultHasher, CryptoHasher};
+use std::collections::VecDeque;
+use vm::errors::VMResult;
+use byteorder::{LittleEndian, ByteOrder};
+use move_core_types::{
+    gas_schedule::{GasUnits, GasAlgebra},
+};
+
+const COST: u64 = 929;
+const PRICE_ORACLE_TAG: u8 = 255;
+
+pub fn native_oracle_get_price(
+    context: &impl NativeContext,
+    _ty_args: Vec<Type>,
+    mut arguments: VecDeque<Value>,
+) -> VMResult<NativeResult> {
+    if arguments.len() != 1 {
+        let msg = format!(
+            "wrong number of arguments for get_price expected 1 found {}",
+            arguments.len()
+        );
+        return Err(status(StatusCode::UNREACHABLE, &msg));
+    }
+
+    let ticker = pop_arg!(arguments, u64);
+    let price =
+        make_path(ticker)
+        .and_then(|path| {
+            let value = context.raw_load(&path).map_err(|err| {
+                status(
+                    StatusCode::STORAGE_ERROR,
+                    &format!("Failed to load ticker [{}]", err),
+                )
+            })?;
+
+            if let Some(price) = value {
+                if price.len() != 8 {
+                    Err(status(StatusCode::TYPE_MISMATCH, "Invalid prise size"))
+                } else {
+                    Ok(LittleEndian::read_u64(&price))
+                }
+            } else {
+                Err(status(StatusCode::STORAGE_ERROR, "Price is not found"))
+            }
+        });
+
+    let cost = GasUnits::new(COST);
+    Ok(match price {
+        Ok(price) => NativeResult::ok(cost, vec![Value::u64(price)]),
+        Err(status) => NativeResult::err(cost, status),
+    })
+}
+
+fn status(code: StatusCode, msg: &str) -> VMStatus {
+    VMStatus::new(code).with_message(msg.to_owned())
+}
+
+pub fn make_path(ticker_pair: u64) -> Result<AccessPath, VMStatus> {
+    let mut hasher = DefaultHasher::default();
+    let mut buf = [0; 8];
+    LittleEndian::write_u64(&mut buf, ticker_pair);
+    hasher.write(&buf);
+    let mut hash = hasher.finish().to_vec();
+    hash.insert(0, PRICE_ORACLE_TAG);
+    Ok(AccessPath::new(AccountAddress::DEFAULT, hash))
+}
+

language/move-vm/runtime/src/native_functions.rs

@@ -7,7 +7,7 @@ use libra_types::{
     contract_event::ContractEvent, language_storage::ModuleId,
 };
 use move_core_types::{gas_schedule::CostTable, identifier::IdentStr};
-use move_vm_natives::{account, event, hash, lcs, signature};
+use move_vm_natives::{account, event, hash, lcs, signature, oracle};
 use move_vm_types::{
     interpreter_context::InterpreterContext,
     loaded_data::{runtime_types::Type, types::FatType},
@@ -43,6 +43,7 @@ pub(crate) enum NativeFunction {
     AccountSaveBalance,
     DebugPrint,
     DebugPrintStackTrace,
+    OraclePrice,
 }
 
 impl NativeFunction {
@@ -75,6 +76,7 @@ impl NativeFunction {
             (&CORE_CODE_ADDRESS, "Account", "save_balance") => AccountSaveBalance,
             (&CORE_CODE_ADDRESS, "Debug", "print") => DebugPrint,
             (&CORE_CODE_ADDRESS, "Debug", "print_stack_trace") => DebugPrintStackTrace,
+            (&CORE_CODE_ADDRESS, "Oracle", "get_price") => OraclePrice,
             _ => return None,
         })
     }
@@ -108,6 +110,7 @@ impl NativeFunction {
             Self::LCSToBytes => lcs::native_to_bytes(ctx, t, v),
             Self::DebugPrint => debug::native_print(ctx, t, v),
             Self::DebugPrintStackTrace => debug::native_print_stack_trace(ctx, t, v),
+            Self::OraclePrice => oracle::native_oracle_get_price(ctx, t, v),
         }
     }
 }
@@ -160,7 +163,9 @@ impl<'a, 'txn> NativeContext for FunctionContext<'a, 'txn> {
         self.interpreter_context
             .move_resource_to(&ap, libra_type.fat_type(), resource_to_save)
     }
-
+    fn raw_load(&self, path: &AccessPath) -> VMResult<Option<Vec<u8>>> {
+        self.interpreter_context.raw_load(path)
+    }
     fn save_event(&mut self, event: ContractEvent) -> VMResult<()> {
         Ok(self.interpreter_context.push_event(event))
     }

language/move-vm/state/src/data_cache.rs

@@ -116,7 +116,7 @@ pub struct TransactionDataCache<'txn> {
     // Also need to relate this to a ResourceKey.
     data_map: BTreeMap<AccessPath, Option<(FatStructType, GlobalValue)>>,
     module_map: BTreeMap<ModuleId, Vec<u8>>,
-    data_cache: &'txn dyn RemoteCache,
+    pub data_cache: &'txn dyn RemoteCache,
 }
 
 impl<'txn> TransactionDataCache<'txn> {

language/move-vm/state/src/execution_context.rs

@@ -128,6 +128,10 @@ impl<'txn> ChainState for TransactionExecutionContext<'txn> {
     fn emit_event(&mut self, event: ContractEvent) {
         self.event_data.push(event)
     }
+
+    fn raw_load(&self, path: &AccessPath) -> VMResult<Option<Vec<u8>>> {
+        self.data_view.data_cache.get(path)
+    }
 }
 
 pub struct SystemExecutionContext<'txn>(TransactionExecutionContext<'txn>);
@@ -200,6 +204,10 @@ impl<'txn> ChainState for SystemExecutionContext<'txn> {
     fn emit_event(&mut self, event: ContractEvent) {
         self.0.emit_event(event)
     }
+
+    fn raw_load(&self, path: &AccessPath) -> VMResult<Option<Vec<u8>>> {
+        self.0.raw_load(path)
+    }
 }
 
 impl<'txn> From<TransactionExecutionContext<'txn>> for SystemExecutionContext<'txn> {

language/move-vm/types/Cargo.toml

@@ -25,6 +25,8 @@ libra-workspace-hack = { path = "../../../common/workspace-hack", version = "0.1
 move-core-types = { path = "../../move-core/types", version = "0.1.0" }
 vm = { path = "../../vm", version = "0.1.0" }
 
+libra-state-view = { path = "../../../storage/state-view", version = "0.1.0"}
+
 [dev-dependencies]
 proptest = "0.9.6"
 

language/move-vm/types/src/chain_state.rs

@@ -34,7 +34,9 @@ pub trait ChainState {
     /// Get the serialized format of a `CompiledModule` from chain given a `ModuleId`.
     fn load_module(&self, module: &ModuleId) -> VMResult<Vec<u8>>;
 
-    /// Get a reference to a resource stored on chain.
+    fn raw_load(&self, path: &AccessPath) -> VMResult<Option<Vec<u8>>>;
+
+        /// Get a reference to a resource stored on chain.
     fn borrow_resource(
         &mut self,
         ap: &AccessPath,

language/move-vm/types/src/interpreter_context.rs

@@ -47,6 +47,8 @@ pub trait InterpreterContext {
     fn load_module(&self, module: &ModuleId) -> VMResult<Vec<u8>>;
 
     fn publish_module(&mut self, module_id: ModuleId, module: Vec<u8>) -> VMResult<()>;
+
+    fn raw_load(&self, path: &AccessPath) -> VMResult<Option<Vec<u8>>>;
 }
 
 impl<T: ChainState> InterpreterContext for T {
@@ -146,4 +148,8 @@ impl<T: ChainState> InterpreterContext for T {
     fn publish_module(&mut self, module_id: ModuleId, module: Vec<u8>) -> VMResult<()> {
         self.publish_module(module_id, module)
     }
+
+    fn raw_load(&self, path: &AccessPath) -> VMResult<Option<Vec<u8>>> {
+        self.raw_load(path)
+    }
 }

language/move-vm/types/src/natives/function.rs

@@ -24,6 +24,7 @@ use crate::{
 use libra_types::{
     account_address::AccountAddress, contract_event::ContractEvent, language_storage::ModuleId,
     vm_error::VMStatus,
+    access_path::AccessPath
 };
 use move_core_types::{
     gas_schedule::{AbstractMemorySize, CostTable, GasAlgebra, GasCarrier, GasUnits},
@@ -52,6 +53,8 @@ pub trait NativeContext {
         resource_to_save: Struct,
         account_address: AccountAddress,
     ) -> VMResult<()>;
+    /// Load from state view.
+    fn raw_load(&self, path: &AccessPath) -> VMResult<Option<Vec<u8>>>;
     /// Saves contract event.
     fn save_event(&mut self, event: ContractEvent) -> VMResult<()>;
     /// Converts types to fet types.

language/tools/vm-genesis/src/genesis_context.rs

@@ -236,4 +236,8 @@ impl<'txn> ChainState for GenesisExecutionContext<'txn> {
     fn emit_event(&mut self, event: ContractEvent) {
         self.ctx.emit_event(event)
     }
+
+    fn raw_load(&self, path: &AccessPath) -> VMResult<Option<Vec<u8>>> {
+        self.ctx.raw_load(path)
+    }
 }