diff options
Diffstat (limited to 'crates/cfg/src')
-rw-r--r-- | crates/cfg/src/lib.rs | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/crates/cfg/src/lib.rs b/crates/cfg/src/lib.rs index 03b8dd767..916d39a0b 100644 --- a/crates/cfg/src/lib.rs +++ b/crates/cfg/src/lib.rs | |||
@@ -1,4 +1,4 @@ | |||
1 | //! cfg defines conditional compiling options, `cfg` attibute parser and evaluator | 1 | //! cfg defines conditional compiling options, `cfg` attribute parser and evaluator |
2 | 2 | ||
3 | mod cfg_expr; | 3 | mod cfg_expr; |
4 | mod dnf; | 4 | mod dnf; |
@@ -52,6 +52,7 @@ impl CfgOptions { | |||
52 | } | 52 | } |
53 | } | 53 | } |
54 | 54 | ||
55 | #[derive(Clone, Debug, PartialEq, Eq)] | ||
55 | pub struct CfgDiff { | 56 | pub struct CfgDiff { |
56 | // Invariants: No duplicates, no atom that's both in `enable` and `disable`. | 57 | // Invariants: No duplicates, no atom that's both in `enable` and `disable`. |
57 | enable: Vec<CfgAtom>, | 58 | enable: Vec<CfgAtom>, |
@@ -59,6 +60,20 @@ pub struct CfgDiff { | |||
59 | } | 60 | } |
60 | 61 | ||
61 | impl CfgDiff { | 62 | impl CfgDiff { |
63 | /// Create a new CfgDiff. Will return None if the same item appears more than once in the set | ||
64 | /// of both. | ||
65 | pub fn new(enable: Vec<CfgAtom>, disable: Vec<CfgAtom>) -> Option<CfgDiff> { | ||
66 | let mut occupied = FxHashSet::default(); | ||
67 | for item in enable.iter().chain(disable.iter()) { | ||
68 | if !occupied.insert(item) { | ||
69 | // was present | ||
70 | return None; | ||
71 | } | ||
72 | } | ||
73 | |||
74 | Some(CfgDiff { enable, disable }) | ||
75 | } | ||
76 | |||
62 | /// Returns the total number of atoms changed by this diff. | 77 | /// Returns the total number of atoms changed by this diff. |
63 | pub fn len(&self) -> usize { | 78 | pub fn len(&self) -> usize { |
64 | self.enable.len() + self.disable.len() | 79 | self.enable.len() + self.disable.len() |