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[framework] Move
features.move into stdlib so it can be used from e…
…verywhere (#4467) This requires unfortunately that the boolean functions checking for features cannot be longer friends (and henceforth need to stay and cannot be remove), but otherwise seems to be straightforward.
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4 changes: 2 additions & 2 deletions
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...mework/sources/configs/features.spec.move → ...stdlib/sources/configs/features.spec.move
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141 changes: 141 additions & 0 deletions
141
...-move-tests/tests/code_publishing.data/pack_stdlib_incompat/sources/configs/features.move
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,141 @@ | ||
| /// Defines feature flags for Aptos. Those are used in Aptos specific implementations of features in | ||
| /// the Move stdlib, the Aptos stdlib, and the Aptos framework. | ||
| module std::features { | ||
| use std::error; | ||
| use std::signer; | ||
| use std::vector; | ||
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| // ============================================================================================ | ||
| // Feature Flag Definitions | ||
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| // Each feature flag should come with documentation which justifies the need of the flag. | ||
| // Introduction of a new feature flag requires approval of framework owners. Be frugal when | ||
| // introducing new feature flags, as too many can make it hard to understand the code. | ||
| // | ||
| // Each feature flag should come with a specification of a lifetime: | ||
| // | ||
| // - a *transient* feature flag is only needed until a related code rollout has happened. This | ||
| // is typically associated with the introduction of new native Move functions, and is only used | ||
| // from Move code. The owner of this feature is obliged to remove it once this can be done. | ||
| // | ||
| // - an *ephemeral* feature flag is required to stay around forever. Typically, those flags guard | ||
| // behavior in native code, and the behavior with or without the feature need to be preserved | ||
| // for playback. | ||
| // | ||
| // Note that removing a feature flag still requires the function which tests for the feature | ||
| // (like `code_dependency_check_enabled` below) to stay around for compatibility reasons, as it | ||
| // is a public function. However, once the feature flag is disabled, those functions can constantly | ||
| // return true. | ||
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| // -------------------------------------------------------------------------------------------- | ||
| // Code Publishing | ||
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| /// Whether validation of package dependencies is enabled, and the related native function is | ||
| /// available. This is needed because of introduction of a new native function. | ||
| /// Lifetime: transient | ||
| const CODE_DEPENDENCY_CHECK: u64 = 1; | ||
| public fun code_dependency_check_enabled(): bool acquires Features { | ||
| is_enabled(CODE_DEPENDENCY_CHECK) | ||
| } | ||
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| /// Whether during upgrade compatibility checking, friend functions should be treated similar like | ||
| /// private functions. | ||
| /// Lifetime: ephemeral | ||
| const TREAT_FRIEND_AS_PRIVATE: u64 = 2; | ||
| public fun treat_friend_as_private(): bool acquires Features { | ||
| is_enabled(TREAT_FRIEND_AS_PRIVATE) | ||
| } | ||
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| // ============================================================================================ | ||
| // Feature Flag Implementation | ||
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| /// The provided signer has not a framework address. | ||
| const EFRAMEWORK_SIGNER_NEEDED: u64 = 1; | ||
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| /// The enabled features, represented by a bitset stored on chain. | ||
| struct Features has key { | ||
| features: vector<u8>, | ||
| } | ||
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| /// Function to enable and disable features. Can only be called by a signer of @std. | ||
| public fun change_feature_flags(framework: &signer, enable: vector<u64>, disable: vector<u64>) | ||
| acquires Features { | ||
| assert!(signer::address_of(framework) == @std, error::permission_denied(EFRAMEWORK_SIGNER_NEEDED)); | ||
| if (!exists<Features>(@std)) { | ||
| move_to<Features>(framework, Features{features: vector[]}) | ||
| }; | ||
| let features = &mut borrow_global_mut<Features>(@std).features; | ||
| let i = 0; | ||
| let n = vector::length(&enable); | ||
| while (i < n) { | ||
| set(features, *vector::borrow(&enable, i), true); | ||
| i = i + 1 | ||
| }; | ||
| let i = 0; | ||
| let n = vector::length(&disable); | ||
| while (i < n) { | ||
| set(features, *vector::borrow(&disable, i), false); | ||
| i = i + 1 | ||
| }; | ||
| } | ||
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| /// Check whether the feature is enabled. | ||
| fun is_enabled(feature: u64): bool acquires Features { | ||
| exists<Features>(@std) && | ||
| contains(&borrow_global<Features>(@std).features, feature) | ||
| } | ||
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| /// Helper to include or exclude a feature flag. | ||
| fun set(features: &mut vector<u8>, feature: u64, include: bool) { | ||
| let byte_index = feature / 8; | ||
| let bit_mask = 1 << ((feature % 8) as u8); | ||
| while (vector::length(features) <= byte_index) { | ||
| vector::push_back(features, 0) | ||
| }; | ||
| let entry = vector::borrow_mut(features, byte_index); | ||
| if (include) | ||
| *entry = *entry | bit_mask | ||
| else | ||
| *entry = *entry & (0xff ^ bit_mask) | ||
| } | ||
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| /// Helper to check whether a feature flag is enabled. | ||
| fun contains(features: &vector<u8>, feature: u64): bool { | ||
| let byte_index = feature / 8; | ||
| let bit_mask = 1 << ((feature % 8) as u8); | ||
| byte_index < vector::length(features) && (*vector::borrow(features, byte_index) & bit_mask) != 0 | ||
| } | ||
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| #[test] | ||
| fun test_feature_sets() { | ||
| let features = vector[]; | ||
| set(&mut features, 1, true); | ||
| set(&mut features, 5, true); | ||
| set(&mut features, 17, true); | ||
| set(&mut features, 23, true); | ||
| assert!(contains(&features, 1), 0); | ||
| assert!(contains(&features, 5), 1); | ||
| assert!(contains(&features, 17), 2); | ||
| assert!(contains(&features, 23), 3); | ||
| set(&mut features, 5, false); | ||
| set(&mut features, 17, false); | ||
| assert!(contains(&features, 1), 0); | ||
| assert!(!contains(&features, 5), 1); | ||
| assert!(!contains(&features, 17), 2); | ||
| assert!(contains(&features, 23), 3); | ||
| } | ||
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| #[test(fx = @std)] | ||
| fun test_change_feature_txn(fx: signer) acquires Features { | ||
| change_feature_flags(&fx, vector[1, 9, 23], vector[]); | ||
| assert!(is_enabled(1), 1); | ||
| assert!(is_enabled(9), 2); | ||
| assert!(is_enabled(23), 3); | ||
| change_feature_flags(&fx, vector[17], vector[9]); | ||
| assert!(is_enabled(1), 1); | ||
| assert!(!is_enabled(9), 2); | ||
| assert!(is_enabled(17), 3); | ||
| assert!(is_enabled(23), 4); | ||
| } | ||
| } |
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...-tests/tests/code_publishing.data/pack_stdlib_incompat/sources/configs/features.spec.move
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,16 @@ | ||
| /// Maintains feature flags. | ||
| spec std::features { | ||
| spec module { | ||
| pragma verify = false; | ||
| } | ||
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| spec change_feature_flags { | ||
| pragma opaque = true; | ||
| modifies global<Features>(@std); | ||
| } | ||
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| spec code_dependency_check_enabled { | ||
| pragma opaque = true; | ||
| } | ||
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| } |
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