    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    59
    60
    61
    62
    63
    64
    65
    66
    67
    68
    69
    70
    71
    72
    73
    74
    75
    76
    77
    78
    79
    80
    81
    82
    83
    84
    85
    86
    87
    88
    89
    90
    91
    92
    93
    94
    95
    96
    97
    98
    99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    114
    115
    116
    117
    118
    119
    120
    121
    122
    123
    124
    125
    126
    127
    128
    129
    130
    131
    132
    133
    134
    135
    136
    137
    138
    139
    140
    141
    142
    143
    144
    145
    146
    147
    148
    149
    150
    151
    152
    153
    154
    155
    156
    157
    158
    159
    160
    161
    162
    163
    164
    165
    166
    167
    168
    169
    170
    171
    172
    173
    174
    175
    176
    177
    178
    179
    180
    181
    182
    183
    184
    185
    186
    187
    188
    189
    190
    191
    192
    193
    194
    195
    196
    197
    198
    199
    200
    201
    202
    203
    204
    205
    206
    207
    208
    209
    210
    211
    212
    213
    214
    215
    216
    217
    218
    219
    220
    221
    222
    223
    224
    225
    226
    227
    228
    229
    230
    231
    232
    233
    234
    235
    236
    237
    238
    239
    240
    241
    242
    243
    244
    245
    246
    247
    248
    249
    250
    251
    252
    253
    254
    255
    256
    257
    258
    259
    260
    261
    262
    263
    264
    265
    266
    267
    268
    269
    270

    use std::fmt;
    use std::fmt::Debug;

    use super::*;
    use crate::core::Shell;

    /// Tells a better story of why a build is considered "dirty" that leads
    /// to a recompile. Usually constructed via [`Fingerprint::compare`].
    ///
    /// [`Fingerprint::compare`]: super::Fingerprint::compare
    #[derive(Clone, Debug)]
    pub enum DirtyReason {
        RustcChanged,
        FeaturesChanged {
            old: String,
            new: String,
        },
        DeclaredFeaturesChanged {
            old: String,
            new: String,
        },
        TargetConfigurationChanged,
        PathToSourceChanged,
        ProfileConfigurationChanged,
        RustflagsChanged {
            old: Vec<String>,
            new: Vec<String>,
        },
        MetadataChanged,
        ConfigSettingsChanged,
        CompileKindChanged,
        LocalLengthsChanged,
        PrecalculatedComponentsChanged {
            old: String,
            new: String,
        },
        DepInfoOutputChanged {
            old: PathBuf,
            new: PathBuf,
        },
        RerunIfChangedOutputFileChanged {
            old: PathBuf,
            new: PathBuf,
        },
        RerunIfChangedOutputPathsChanged {
            old: Vec<PathBuf>,
            new: Vec<PathBuf>,
        },
        EnvVarsChanged {
            old: String,
            new: String,
        },
        EnvVarChanged {
            name: String,
            old_value: Option<String>,
            new_value: Option<String>,
        },
        LocalFingerprintTypeChanged {
            old: &'static str,
            new: &'static str,
        },
        NumberOfDependenciesChanged {
            old: usize,
            new: usize,
        },
        UnitDependencyNameChanged {
            old: InternedString,
            new: InternedString,
        },
        UnitDependencyInfoChanged {
            old_name: InternedString,
            old_fingerprint: u64,

            new_name: InternedString,
            new_fingerprint: u64,
        },
        FsStatusOutdated(FsStatus),
        NothingObvious,
        Forced,
        /// First time to build something.
        FreshBuild,
    }

    trait ShellExt {
        fn dirty_because(&mut self, unit: &Unit, s: impl fmt::Display) -> CargoResult<()>;
    }

    impl ShellExt for Shell {
        fn dirty_because(&mut self, unit: &Unit, s: impl fmt::Display) -> CargoResult<()> {
            self.status("Dirty", format_args!("{}: {s}", &unit.pkg))
        }
    }

    struct FileTimeDiff {
        old_time: FileTime,
        new_time: FileTime,
    }

    impl fmt::Display for FileTimeDiff {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            let s_diff = self.new_time.seconds() - self.old_time.seconds();
            if s_diff >= 1 {
                fmt::Display::fmt(
                    &humantime::Duration::from(std::time::Duration::from_secs(s_diff as u64)),
                    f,
                )
            } else {
                // format nanoseconds as it is, humantime would display ms, us and ns
                let ns_diff = self.new_time.nanoseconds() - self.old_time.nanoseconds();
                write!(f, "{ns_diff}ns")
            }
        }
    }

    #[derive(Copy, Clone)]
    struct After {
        old_time: FileTime,
        new_time: FileTime,
        what: &'static str,
    }

    impl fmt::Display for After {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            let Self {
                old_time,
                new_time,
                what,
            } = *self;
            let diff = FileTimeDiff { old_time, new_time };

            write!(f, "{new_time}, {diff} after {what} at {old_time}")
        }
    }

    impl DirtyReason {
        /// Whether a build is dirty because it is a fresh build being kicked off.
        pub fn is_fresh_build(&self) -> bool {
            matches!(self, DirtyReason::FreshBuild)
        }

        fn after(old_time: FileTime, new_time: FileTime, what: &'static str) -> After {
            After {
                old_time,
                new_time,
                what,
            }
        }

        pub fn present_to(&self, s: &mut Shell, unit: &Unit, root: &Path) -> CargoResult<()> {
            match self {
                DirtyReason::RustcChanged => s.dirty_because(unit, "the toolchain changed"),
                DirtyReason::FeaturesChanged { .. } => {
                    s.dirty_because(unit, "the list of features changed")
                }
                DirtyReason::DeclaredFeaturesChanged { .. } => {
                    s.dirty_because(unit, "the list of declared features changed")
                }
                DirtyReason::TargetConfigurationChanged => {
                    s.dirty_because(unit, "the target configuration changed")
                }
                DirtyReason::PathToSourceChanged => {
                    s.dirty_because(unit, "the path to the source changed")
                }
                DirtyReason::ProfileConfigurationChanged => {
                    s.dirty_because(unit, "the profile configuration changed")
                }
                DirtyReason::RustflagsChanged { .. } => s.dirty_because(unit, "the rustflags changed"),
                DirtyReason::MetadataChanged => s.dirty_because(unit, "the metadata changed"),
                DirtyReason::ConfigSettingsChanged => {
                    s.dirty_because(unit, "the config settings changed")
                }
                DirtyReason::CompileKindChanged => {
                    s.dirty_because(unit, "the rustc compile kind changed")
                }
                DirtyReason::LocalLengthsChanged => {
                    s.dirty_because(unit, "the local lengths changed")?;
                    s.note(
                        "this could happen because of added/removed `cargo::rerun-if` instructions in the build script",
                    )?;

                    Ok(())
                }
                DirtyReason::PrecalculatedComponentsChanged { .. } => {
                    s.dirty_because(unit, "the precalculated components changed")
                }
                DirtyReason::DepInfoOutputChanged { .. } => {
                    s.dirty_because(unit, "the dependency info output changed")
                }
                DirtyReason::RerunIfChangedOutputFileChanged { .. } => {
                    s.dirty_because(unit, "rerun-if-changed output file path changed")
                }
                DirtyReason::RerunIfChangedOutputPathsChanged { .. } => {
                    s.dirty_because(unit, "the rerun-if-changed instructions changed")
                }
                DirtyReason::EnvVarsChanged { .. } => {
                    s.dirty_because(unit, "the environment variables changed")
                }
                DirtyReason::EnvVarChanged { name, .. } => {
                    s.dirty_because(unit, format_args!("the env variable {name} changed"))
                }
                DirtyReason::LocalFingerprintTypeChanged { .. } => {
                    s.dirty_because(unit, "the local fingerprint type changed")
                }
                DirtyReason::NumberOfDependenciesChanged { old, new } => s.dirty_because(
                    unit,
                    format_args!("number of dependencies changed ({old} => {new})",),
                ),
                DirtyReason::UnitDependencyNameChanged { old, new } => s.dirty_because(
                    unit,
                    format_args!("name of dependency changed ({old} => {new})"),
                ),
                DirtyReason::UnitDependencyInfoChanged { .. } => {
                    s.dirty_because(unit, "dependency info changed")
                }
                DirtyReason::FsStatusOutdated(status) => match status {
                    FsStatus::Stale => s.dirty_because(unit, "stale, unknown reason"),
                    FsStatus::StaleItem(item) => match item {
                        StaleItem::MissingFile(missing_file) => {
                            let file = missing_file.strip_prefix(root).unwrap_or(&missing_file);
                            s.dirty_because(
                                unit,
                                format_args!("the file `{}` is missing", file.display()),
                            )
                        }
                        StaleItem::ChangedFile {
                            stale,
                            stale_mtime,
                            reference_mtime,
                            ..
                        } => {
                            let file = stale.strip_prefix(root).unwrap_or(&stale);
                            let after = Self::after(*reference_mtime, *stale_mtime, "last build");
                            s.dirty_because(
                                unit,
                                format_args!("the file `{}` has changed ({after})", file.display()),
                            )
                        }
                        StaleItem::ChangedEnv { var, .. } => s.dirty_because(
                            unit,
                            format_args!("the environment variable {var} changed"),
                        ),
                    },
                    FsStatus::StaleDependency {
                        name,
                        dep_mtime,
                        max_mtime,
                        ..
                    } => {
                        let after = Self::after(*max_mtime, *dep_mtime, "last build");
                        s.dirty_because(
                            unit,
                            format_args!("the dependency {name} was rebuilt ({after})"),
                        )
                    }
                    FsStatus::StaleDepFingerprint { name } => {
                        s.dirty_because(unit, format_args!("the dependency {name} was rebuilt"))
                    }
                    FsStatus::UpToDate { .. } => {
                        unreachable!()
                    }
                },
                DirtyReason::NothingObvious => {
                    // See comment in fingerprint compare method.
                    s.dirty_because(unit, "the fingerprint comparison turned up nothing obvious")
                }
                DirtyReason::Forced => s.dirty_because(unit, "forced"),
                DirtyReason::FreshBuild => s.dirty_because(unit, "fresh build"),
            }
        }
    }