gix_refspec/
parse.rs

1/// The error returned by the [`parse()`][crate::parse()] function.
2#[derive(Debug, thiserror::Error)]
3#[allow(missing_docs)]
4pub enum Error {
5    #[error("Empty refspecs are invalid")]
6    Empty,
7    #[error("Negative refspecs cannot have destinations as they exclude sources")]
8    NegativeWithDestination,
9    #[error("Negative specs must not be empty")]
10    NegativeEmpty,
11    #[error("Negative specs must be object hashes")]
12    NegativeObjectHash,
13    #[error("Negative specs must be full ref names, starting with \"refs/\"")]
14    NegativePartialName,
15    #[error("Negative glob patterns are not allowed")]
16    NegativeGlobPattern,
17    #[error("Fetch destinations must be ref-names, like 'HEAD:refs/heads/branch'")]
18    InvalidFetchDestination,
19    #[error("Cannot push into an empty destination")]
20    PushToEmpty,
21    #[error("glob patterns may only involved a single '*' character, found {pattern:?}")]
22    PatternUnsupported { pattern: bstr::BString },
23    #[error("Both sides of the specification need a pattern, like 'a/*:b/*'")]
24    PatternUnbalanced,
25    #[error(transparent)]
26    ReferenceName(#[from] gix_validate::reference::name::Error),
27    #[error(transparent)]
28    RevSpec(#[from] gix_revision::spec::parse::Error),
29}
30
31/// Define how the parsed refspec should be used.
32#[derive(PartialOrd, Ord, PartialEq, Eq, Copy, Clone, Hash, Debug)]
33pub enum Operation {
34    /// The `src` side is local and the `dst` side is remote.
35    Push,
36    /// The `src` side is remote and the `dst` side is local.
37    Fetch,
38}
39
40pub(crate) mod function {
41    use bstr::{BStr, ByteSlice};
42
43    use crate::{
44        parse::{Error, Operation},
45        types::Mode,
46        RefSpecRef,
47    };
48
49    /// Parse `spec` for use in `operation` and return it if it is valid.
50    pub fn parse(mut spec: &BStr, operation: Operation) -> Result<RefSpecRef<'_>, Error> {
51        fn fetch_head_only(mode: Mode) -> RefSpecRef<'static> {
52            RefSpecRef {
53                mode,
54                op: Operation::Fetch,
55                src: Some("HEAD".into()),
56                dst: None,
57            }
58        }
59
60        let mode = match spec.first() {
61            Some(&b'^') => {
62                spec = &spec[1..];
63                Mode::Negative
64            }
65            Some(&b'+') => {
66                spec = &spec[1..];
67                Mode::Force
68            }
69            Some(_) => Mode::Normal,
70            None => {
71                return match operation {
72                    Operation::Push => Err(Error::Empty),
73                    Operation::Fetch => Ok(fetch_head_only(Mode::Normal)),
74                }
75            }
76        };
77
78        let (mut src, dst) = match spec.find_byte(b':') {
79            Some(pos) => {
80                if mode == Mode::Negative {
81                    return Err(Error::NegativeWithDestination);
82                }
83
84                let (src, dst) = spec.split_at(pos);
85                let dst = &dst[1..];
86                let src = (!src.is_empty()).then(|| src.as_bstr());
87                let dst = (!dst.is_empty()).then(|| dst.as_bstr());
88                match (src, dst) {
89                    (None, None) => match operation {
90                        Operation::Push => (None, None),
91                        Operation::Fetch => (Some("HEAD".into()), None),
92                    },
93                    (None, Some(dst)) => match operation {
94                        Operation::Push => (None, Some(dst)),
95                        Operation::Fetch => (Some("HEAD".into()), Some(dst)),
96                    },
97                    (Some(src), None) => match operation {
98                        Operation::Push => return Err(Error::PushToEmpty),
99                        Operation::Fetch => (Some(src), None),
100                    },
101                    (Some(src), Some(dst)) => (Some(src), Some(dst)),
102                }
103            }
104            None => {
105                let src = (!spec.is_empty()).then_some(spec);
106                if Operation::Fetch == operation && mode != Mode::Negative && src.is_none() {
107                    return Ok(fetch_head_only(mode));
108                } else {
109                    (src, None)
110                }
111            }
112        };
113
114        if let Some(spec) = src.as_mut() {
115            if *spec == "@" {
116                *spec = "HEAD".into();
117            }
118        }
119        let (src, src_had_pattern) = validated(src, operation == Operation::Push && dst.is_some())?;
120        let (dst, dst_had_pattern) = validated(dst, false)?;
121        if mode != Mode::Negative && src_had_pattern != dst_had_pattern {
122            return Err(Error::PatternUnbalanced);
123        }
124
125        if mode == Mode::Negative {
126            match src {
127                Some(spec) => {
128                    if src_had_pattern {
129                        return Err(Error::NegativeGlobPattern);
130                    } else if looks_like_object_hash(spec) {
131                        return Err(Error::NegativeObjectHash);
132                    } else if !spec.starts_with(b"refs/") && spec != "HEAD" {
133                        return Err(Error::NegativePartialName);
134                    }
135                }
136                None => return Err(Error::NegativeEmpty),
137            }
138        }
139
140        Ok(RefSpecRef {
141            op: operation,
142            mode,
143            src,
144            dst,
145        })
146    }
147
148    fn looks_like_object_hash(spec: &BStr) -> bool {
149        spec.len() >= gix_hash::Kind::shortest().len_in_hex() && spec.iter().all(u8::is_ascii_hexdigit)
150    }
151
152    fn validated(spec: Option<&BStr>, allow_revspecs: bool) -> Result<(Option<&BStr>, bool), Error> {
153        match spec {
154            Some(spec) => {
155                let glob_count = spec.iter().filter(|b| **b == b'*').take(2).count();
156                if glob_count > 1 {
157                    return Err(Error::PatternUnsupported { pattern: spec.into() });
158                }
159                let has_globs = glob_count == 1;
160                if has_globs {
161                    let mut buf = smallvec::SmallVec::<[u8; 256]>::with_capacity(spec.len());
162                    buf.extend_from_slice(spec);
163                    let glob_pos = buf.find_byte(b'*').expect("glob present");
164                    buf[glob_pos] = b'a';
165                    gix_validate::reference::name_partial(buf.as_bstr())?;
166                } else {
167                    gix_validate::reference::name_partial(spec)
168                        .map_err(Error::from)
169                        .or_else(|err| {
170                            if allow_revspecs {
171                                gix_revision::spec::parse(spec, &mut super::revparse::Noop)?;
172                                Ok(spec)
173                            } else {
174                                Err(err)
175                            }
176                        })?;
177                }
178                Ok((Some(spec), has_globs))
179            }
180            None => Ok((None, false)),
181        }
182    }
183}
184
185mod revparse {
186    use bstr::BStr;
187    use gix_revision::spec::parse::delegate::{
188        Kind, Navigate, PeelTo, PrefixHint, ReflogLookup, Revision, SiblingBranch, Traversal,
189    };
190
191    pub(crate) struct Noop;
192
193    impl Revision for Noop {
194        fn find_ref(&mut self, _name: &BStr) -> Option<()> {
195            Some(())
196        }
197
198        fn disambiguate_prefix(&mut self, _prefix: gix_hash::Prefix, _hint: Option<PrefixHint<'_>>) -> Option<()> {
199            Some(())
200        }
201
202        fn reflog(&mut self, _query: ReflogLookup) -> Option<()> {
203            Some(())
204        }
205
206        fn nth_checked_out_branch(&mut self, _branch_no: usize) -> Option<()> {
207            Some(())
208        }
209
210        fn sibling_branch(&mut self, _kind: SiblingBranch) -> Option<()> {
211            Some(())
212        }
213    }
214
215    impl Navigate for Noop {
216        fn traverse(&mut self, _kind: Traversal) -> Option<()> {
217            Some(())
218        }
219
220        fn peel_until(&mut self, _kind: PeelTo<'_>) -> Option<()> {
221            Some(())
222        }
223
224        fn find(&mut self, _regex: &BStr, _negated: bool) -> Option<()> {
225            Some(())
226        }
227
228        fn index_lookup(&mut self, _path: &BStr, _stage: u8) -> Option<()> {
229            Some(())
230        }
231    }
232
233    impl Kind for Noop {
234        fn kind(&mut self, _kind: gix_revision::spec::Kind) -> Option<()> {
235            Some(())
236        }
237    }
238
239    impl gix_revision::spec::parse::Delegate for Noop {
240        fn done(&mut self) {}
241    }
242}
gix_refspec/parse.rs

gix_refspec/
parse.rs
