Grcov report - revision.rs

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use std::fmt::{Debug, Display, Write};

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use serde::{Deserialize, Serialize};

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use sha2::{Digest, Sha256};

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/// Information about a `Document`'s revision history.

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155738180

#[derive(Clone, Copy, Eq, PartialEq, Serialize, Deserialize, Hash)]

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pub struct Revision {

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    /// The current revision id of the document. This value is sequentially incremented on each document update.

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    pub id: u32,

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    /// The SHA256 digest of the bytes contained within the `Document`.

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    pub sha256: [u8; 32],

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impl Revision {

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    /// Creates the first revision for a document with the SHA256 digest of the passed bytes.

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    #[must_use]

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1058046

    pub fn new(contents: &[u8]) -> Self {

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1058046

        Self::with_id(0, contents)

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1058046

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    /// Creates a revision with `id` for a document with the SHA256 digest of the passed bytes.

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    #[must_use]

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    pub fn with_id(id: u32, contents: &[u8]) -> Self {

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1058046

        Self {

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id,

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            sha256: digest(contents),

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1058046

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1058046

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    /// Creates the next revision in sequence with an updated digest. If the digest doesn't change, None is returned.

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///

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    /// # Panics

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///

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    /// Panics if `id` overflows.

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    #[must_use]

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236884

    pub fn next_revision(&self, new_contents: &[u8]) -> Option<Self> {

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236884

        let sha256 = digest(new_contents);

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        if sha256 == self.sha256 {

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642

            None

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        } else {

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            Some(Self {

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                id: self

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.id

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                    .checked_add(1)

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                    .expect("need to implement revision id wrapping or increase revision id size"),

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                sha256,

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})

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236884

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impl Debug for Revision {

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681

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

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681

        write!(f, "Revision({self})")

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681

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impl Display for Revision {

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

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        <u32 as Display>::fmt(&self.id, f)?;

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        f.write_char('-')?;

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        for byte in self.sha256 {

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            f.write_fmt(format_args!("{byte:02x}"))?;

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        Ok(())

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683

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1294930

fn digest(payload: &[u8]) -> [u8; 32] {

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    let mut hasher = Sha256::default();

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    hasher.update(payload);

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1294930

    hasher.finalize().into()

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1294930

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1

#[test]

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1

fn revision_tests() {

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    let original_contents = b"one";

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    let first_revision = Revision::new(original_contents);

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    let original_digest =

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        hex_literal::hex!("7692c3ad3540bb803c020b3aee66cd8887123234ea0c6e7143c0add73ff431ed");

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    assert_eq!(

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        first_revision,

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        Revision {

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            id: 0,

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            sha256: original_digest

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1

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);

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    assert!(first_revision.next_revision(original_contents).is_none());

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    let updated_contents = b"two";

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    let next_revision = first_revision

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        .next_revision(updated_contents)

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        .expect("new contents should create a new revision");

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    assert_eq!(

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        next_revision,

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        Revision {

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            id: 1,

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            sha256: hex_literal::hex!(

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                "3fc4ccfe745870e2c0d99f71f30ff0656c8dedd41cc1d7d3d376b0dbe685e2f3"

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1

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1

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);

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    assert!(next_revision.next_revision(updated_contents).is_none());

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    assert_eq!(

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        next_revision.next_revision(original_contents),

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        Some(Revision {

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            id: 2,

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            sha256: original_digest

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1

})

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1

);

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1

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#[test]

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fn revision_display_test() {

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    let original_contents = b"one";

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    let first_revision = Revision::new(original_contents);

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    assert_eq!(

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        first_revision.to_string(),

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        "0-7692c3ad3540bb803c020b3aee66cd8887123234ea0c6e7143c0add73ff431ed"

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);

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    assert_eq!(

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        format!("{first_revision:?}"),

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        "Revision(0-7692c3ad3540bb803c020b3aee66cd8887123234ea0c6e7143c0add73ff431ed)"

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1

);

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1