This reverts commit a3339a3950825cc69cf53d37fb786b41e793088b.

The above commit seems to be the cause of internal errors when used: deserialize_str trying to deserialize a principal.

Caused by:
    0: input: 4449444c016c01b3c4b1f204680100_0109010400000000000001
       table: type table0 = record { 1_313_628_723 : principal }
       wire_type: principal, expect_type: principal
    1: Deserialize error: Internal error at /home/runner/.cargo/registry/src/github.com-1ecc6299db9ec823/candid-0.7.3/src/de.rs:459. Please file a bug.))', /home/runner/work/agent-rs/agent-rs/main/ref-tests/src/utils.rs:96:23

data=[10, 116, 105, 100, 0, 0, 0, 0, 0, 144, 0, 51, 1, 1, 0, 0, 0, 4] javascript codePrincipal.fromUint8Array(data) that works well, rust code Principal::try_from_slice(data) that will throw a error(BufferTooLong)

"dependencies": { (javascript)
"@dfinity/principal": "^0.10.2"
}

[dependencies](rust)
ic-types = "0.3.0"

We believe candid is a better place for Principal. It makes dependency management easier. The relevant PR for candid is: https://github.com/dfinity/candid/pull/378

ic-types now only has hash_tree module.

This refactor introduced breaking changes, so bumped up version to 0.4.0-beta.0.

Breaking changes

• Remove PrincipalInner
  • Principal directly holds len and bytes fields
• PrincipalError enum has different set of variants reflecting changes in from_text logic.
• from_text accepts input containing uppercase letters which results in Err before.
• from_text verifies CRC32 check sequence

Implementation details

• Mark Principal::from_slice as deprecated
  • It panics if input longer than 29 bytes
  • recommend to use try_from_slice
• Move all tests to root/tests folder so that we only test public visible behavior
• Use data-encoding instead of base32
  • base32 wrongly accepts invalid base32 string which makes error handling in from_text not clear
  • data-encoding is better maintained and has more dependents and downloads
• Use serde_test
  • serde_json and serde_cbor are kept in dev-dependencies because of doc-tests
• Use impl::impl! macro to verify the necessary traits are implemented

Discussion about data layout

struct Principal(PrincipleInner);
#[repr(packed)]
struct PrincipleInner {
  len: u8,
  bytes: [u8; 29],
}

After removing the layer of PrincipalInner, it becomes:

#[repr(packed)]
struct Principal {
  len: u8,
  bytes: [u8; 29],
}

I'm not sure whether we should keep the repr(packed) here. The Rust Nomicon says:

repr(packed) forces Rust to strip any padding, and only align the type to a byte. This may improve the memory footprint, but will likely have other negative side-effects.

https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=8b19c6d46a7600f575cc936c9dd746ca With or without repr(packed), the type always has size of 30.

The cost of using a recursive function in copying some bytes is not negligible and actually shows up as a cost center in flamegraph.

The fix is simple: use a while loop to do the copy.

A stable Candid interface is coming, so it'd be nice to have the related types publicly available. Types we might want to expose:

• Vocabulary types: AccountIdentifier, Subaccount, ICPTs, etc.
• Request types: AccountBalanceArgs, TransferArgs, etc.
• Error variants (TransferError).

from_slice is still useful when creating global const value:

pub const MAINNET_LEDGER_CANISTER_ID: Principal =
    Principal::from_slice(&[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x01, 0x01]);

try_from_slice needs unwrap() which is not allowed here.

The deserialization path shows up in flamegraph analysis when we ran performance test.

So maybe it is worth special casing since it doesn't need to go through the const function.

Otherwise one might think it comes from https://github.com/dfinity/ic/tree/master/rs/types

See https://doc.rust-lang.org/cargo/reference/manifest.html#the-repository-field

This change changes the display tree labels to be more concervative.

Before, we printed everything that is valid UTF-8 as strings. This causes problems if the input is a byte string with lots of zeros.

For example, canister id 0x00000000000000070101 gets printed as "" in my terminal.

After this change, we will only print blobs as strings if all the bytes are graphic ASCII characters.

Before:

$ cargo outdated -R
Name        Project  Compat   Latest   Kind         Platform
----        -------  ------   ------   ----         --------
serde       1.0.126  1.0.127  1.0.127  Normal       ---
serde_cbor  0.11.1   0.11.2   0.11.2   Development  ---
serde_json  1.0.64   1.0.66   1.0.66   Development  ---
thiserror   1.0.25   1.0.26   1.0.26   Normal       ---

After:

$ cargo outdated -R
All dependencies are up to date, yay!