Struct FileIdentity 

pub struct FileIdentity {
    pub path: PathBuf,
    pub len: u64,
    pub modified: SystemTime,
    pub changed: Option<(i64, i64)>,
}

The on-disk identity a recorded file digest describes.

The same trade [VerifiedBlob] makes for CAS reads, offered to shims for the files they hash: an overwrite moves the modification time and a truncation changes the length, so a digest recorded against both stands until either does. Where the platform reports a metadata-change time the identity carries that too, and it is the part a writer cannot restore: a rewrite that puts the modification time back still moves the change time, so only filesystems without one fall back to the freshness model the surrounding build tool already lives on.

Fields

path: PathBuf

Absolute path of the file.

len: u64

Length of the file in bytes.

modified: SystemTime

Modification time of the file.

changed: Option<(i64, i64)>

Platform metadata-change token, where one exists.

Implementations

impl FileIdentity

pub fn describe(path: &Path, metadata: &Metadata) -> Option<Self>

Describe a file from metadata already in hand, or nothing when the filesystem reports no modification time to compare against later.

pub fn still_describes(&self) -> Result<bool>

Whether the file at this identity’s path still has exactly this identity, so the digest recorded against it still describes the bytes on disk without reading them again.

Length alone would miss an overwrite that keeps the size, and the modification time can be put back by whoever rewrote the file. The change time cannot be set from user space, so where the platform reports one a rewrite that restores the old modification time still shows. A file that has vanished is an error rather than a change, so the caller can tell the two apart.

Trait Implementations

impl Clone for FileIdentity

fn clone(&self) -> FileIdentity

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FileIdentity

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for FileIdentity

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for FileIdentity

impl PartialEq for FileIdentity

fn eq(&self, other: &FileIdentity) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for FileIdentity

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for FileIdentity