API Reference

Complete API documentation for Snapshot Comparison.

Structs

SnapshotStore

Manages snapshot storage and operations.

pub struct SnapshotStore {
    base_dir: PathBuf,
}

Methods

new

pub fn new(base_dir: PathBuf) -> Self

Create a new snapshot store.

Arguments:

• base_dir - Directory to store snapshots

Example:

let store = SnapshotStore::new(PathBuf::from("snapshots"));

base_dir

pub fn base_dir(&self) -> &Path

Get the base directory for this store.

create

pub fn create(
    &self,
    name: &str,
    content: &[u8],
    config: &SnapshotConfig
) -> Result<Snapshot, SnapshotError>

Create a new snapshot.

Arguments:

• name - Snapshot name (no path separators)
• content - Content to store
• config - Configuration options

Returns:

• Ok(Snapshot) - The created snapshot
• Err(SnapshotError) - On failure

read

pub fn read(&self, name: &str) -> Result<Snapshot, SnapshotError>

Read a snapshot from disk.

check

pub fn check(
    &self,
    name: &str,
    content: &[u8],
    config: &SnapshotConfig
) -> Result<CompareResult, SnapshotError>

Compare content against a stored snapshot.

Returns:

• CompareResult::Match - Content matches
• CompareResult::Mismatch { diff, .. } - Content differs
• CompareResult::Updated { .. } - Updated (if update_mode)

update

pub fn update(
    &self,
    name: &str,
    content: &[u8],
    config: &SnapshotConfig
) -> Result<Snapshot, SnapshotError>

Update an existing snapshot.

delete

pub fn delete(&self, name: &str) -> Result<(), SnapshotError>

Delete a snapshot.

list

pub fn list(&self) -> Result<Vec<SnapshotMetadata>, SnapshotError>

List all snapshots.

clean

pub fn clean(
    &self,
    keep: &[&str],
    dry_run: bool
) -> Result<Vec<String>, SnapshotError>

Remove snapshots not in the keep list.

Arguments:

• keep - Names of snapshots to keep
• dry_run - If true, don't actually delete

Returns: Names of (would-be) deleted snapshots

---

SnapshotConfig

Configuration for snapshot operations.

pub struct SnapshotConfig {
    pub file_type: Option<FileType>,
    pub color: bool,
    pub context_lines: usize,
    pub update_mode: bool,
}

Fields

Field	Type	Default	Description
file_type	Option<FileType>	None	File type hint (None = auto-detect)
color	bool	false	Enable colored diff output
context_lines	usize	3	Number of context lines in diffs
update_mode	bool	false	Auto-update on mismatch

Default

impl Default for SnapshotConfig {
    fn default() -> Self {
        Self {
            file_type: None,
            color: false,
            context_lines: 3,
            update_mode: false,
        }
    }
}

---

Snapshot

A stored snapshot with metadata and content.

pub struct Snapshot {
    pub metadata: SnapshotMetadata,
    pub content: Vec<u8>,
}

---

SnapshotMetadata

Metadata about a snapshot.

pub struct SnapshotMetadata {
    pub name: String,
    pub created_at: u64,
    pub updated_at: u64,
    pub content_hash: String,
    pub size: usize,
    pub file_type: FileType,
}

Fields

Field	Type	Description
name	String	Snapshot name
created_at	u64	Unix timestamp of creation
updated_at	u64	Unix timestamp of last update
content_hash	String	FNV-1a hash (hex string)
size	usize	Content size in bytes
file_type	FileType	Detected/specified file type

---

Enums

CompareResult

Result of a snapshot comparison.

pub enum CompareResult {
    Match,
    Mismatch {
        snapshot: Snapshot,
        actual: Vec<u8>,
        diff: DiffOutput,
    },
    Updated {
        old_snapshot: Snapshot,
        new_content: Vec<u8>,
    },
}

Variants

Match

Content matches the stored snapshot exactly.

Mismatch

Content differs from the snapshot.

Field	Type	Description
snapshot	Snapshot	The stored snapshot
actual	Vec<u8>	The content being compared
diff	DiffOutput	Detailed diff result

Updated

Snapshot was updated (only in update_mode).

Field	Type	Description
old_snapshot	Snapshot	Previous snapshot
new_content	Vec<u8>	New content stored

Methods

impl CompareResult {
    pub fn matches(&self) -> bool;
    pub fn was_updated(&self) -> bool;
    pub fn diff(&self) -> Option<&DiffOutput>;
}

---

FileType

Supported file types.

pub enum FileType {
    Text,
    Json,
    Binary,
}

Re-exported from output_diffing_utility.

---

DiffOutput

Diff result from comparison.

pub enum DiffOutput {
    Text(TextDiffResult),
    Json(JsonDiffResult),
    Binary(BinaryDiffResult),
}

Methods

format

pub fn format(&self, snapshot_name: &str, color: bool) -> String

Format the diff as a human-readable string.

has_changes

pub fn has_changes(&self) -> bool

Check if there are any changes.

---

SnapshotError

Error types for snapshot operations.

pub enum SnapshotError {
    NotFound(String),
    IoError(String),
    InvalidName(String),
    CorruptedSnapshot(String),
    InvalidUtf8(String),
}

Variants

Variant	Description
NotFound(name)	Snapshot does not exist
IoError(msg)	File system error
InvalidName(name)	Name contains forbidden characters
CorruptedSnapshot(msg)	Snapshot file is corrupted
InvalidUtf8(msg)	Content is not valid UTF-8

Traits

• std::error::Error
• std::fmt::Display
• std::fmt::Debug
• Clone
• PartialEq
• Eq

---

Functions

hash_content

pub fn hash_content(content: &[u8]) -> u64

Compute FNV-1a hash of content.

format_hash

pub fn format_hash(hash: u64) -> String

Format hash as 16-character hex string.

---

Re-exports

From output_diffing_utility:

pub use output_diffing_utility::FileType;

---

Constants

Validation

• Maximum snapshot name length: 255 characters
• Forbidden characters: /, \, .., \0

File Format

• Extension: .snap
• Header delimiter: ---
• Header prefix: #