Include default values in storage metadata (#1264)

* Add a 'default' field to metadata. It contains code to generate the
default value.

* wasm update

* Make 'default' field an `Option`

* Boxed fn is not static, that won't be fine

* static fn won't do it to as it cannot get T param, will try fat trait

* Fat pointer over phantom data compatible with static instantiation

* DecodeDifferent is cool, using it for decoding.

* using once cell to do what would require copying lazy_static internals.

* Remove cache when no_std (non compatible deps)

* wasm bins update

* Fuse tooling struct and enum derive.

substrate/srml/support/src/storage/generator.rs

@@ -55,7 +55,8 @@ pub use rstd::marker::PhantomData;
 
 pub use srml_metadata::{
 	DecodeDifferent, StorageMetadata, StorageFunctionMetadata,
-	StorageFunctionType, StorageFunctionModifier
+	StorageFunctionType, StorageFunctionModifier,
+	DefaultByte, DefaultByteGetter,
 };
 
 /// Abstraction around storage.
@@ -525,6 +526,7 @@ mod tests {
 	use std::cell::RefCell;
 	use codec::Codec;
 	use super::*;
+	use rstd::marker::PhantomData;
 
 	impl Storage for RefCell<HashMap<Vec<u8>, Vec<u8>>> {
 		fn exists(&self, key: &[u8]) -> bool {
@@ -657,80 +659,117 @@ mod tests {
 				name: DecodeDifferent::Encode("U32"),
 				modifier: StorageFunctionModifier::Optional,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructU32(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[ " Hello, this is doc!" ]),
 			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("PUBU32"),
 				modifier: StorageFunctionModifier::Optional,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructPUBU32(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("U32MYDEF"),
 				modifier: StorageFunctionModifier::Optional,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructU32MYDEF(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("PUBU32MYDEF"),
 				modifier: StorageFunctionModifier::Optional,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructPUBU32MYDEF(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
-
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("GETU32"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("T::Origin")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructGETU32(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("PUBGETU32"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructPUBGETU32(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("GETU32WITHCONFIG"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructGETU32WITHCONFIG(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("PUBGETU32WITHCONFIG"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructPUBGETU32WITHCONFIG(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
-
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("GETU32MYDEF"),
 				modifier: StorageFunctionModifier::Optional,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructGETU32MYDEF(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("PUBGETU32MYDEF"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructPUBGETU32MYDEF(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("GETU32WITHCONFIGMYDEF"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructGETU32WITHCONFIGMYDEF(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("PUBGETU32WITHCONFIGMYDEF"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructPUBGETU32WITHCONFIGMYDEF(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("PUBGETU32WITHCONFIGMYDEFOPT"),
 				modifier: StorageFunctionModifier::Optional,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("u32")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructPUBGETU32WITHCONFIGMYDEFOPT(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 
@@ -740,6 +779,9 @@ mod tests {
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
 				},
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructMAPU32(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
@@ -748,6 +790,9 @@ mod tests {
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
 				},
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructPUBMAPU32(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
@@ -756,6 +801,9 @@ mod tests {
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
 				},
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructMAPU32MYDEF(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
@@ -764,15 +812,20 @@ mod tests {
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
 				},
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructPUBMAPU32MYDEF(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
-
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("GETMAPU32"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
 				},
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructGETMAPU32(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
@@ -781,15 +834,20 @@ mod tests {
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
 				},
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructPUBGETMAPU32(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
-
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("GETMAPU32MYDEF"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
 				},
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructGETMAPU32MYDEF(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
@@ -798,24 +856,36 @@ mod tests {
 				ty: StorageFunctionType::Map{
 					key: DecodeDifferent::Encode("u32"), value: DecodeDifferent::Encode("String")
 				},
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructPUBGETMAPU32MYDEF(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("COMPLEX_TYPE1"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("::std::vec::Vec<<T as Trait>::Origin>")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructCOMPLEX_TYPE1(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("COMPLEX_TYPE2"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("(Vec<Vec<(u16, Box<()>)>>, u32)")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructCOMPLEX_TYPE2(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 			StorageFunctionMetadata {
 				name: DecodeDifferent::Encode("COMPLEX_TYPE3"),
 				modifier: StorageFunctionModifier::Default,
 				ty: StorageFunctionType::Plain(DecodeDifferent::Encode("([u32; 25])")),
+				default: DecodeDifferent::Encode(
+					DefaultByteGetter(&__GetByteStructCOMPLEX_TYPE3(PhantomData::<TraitImpl>))
+				),
 				documentation: DecodeDifferent::Encode(&[]),
 			},
 		])