Grcov report - view-examples.rs

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use bonsaidb::core::document::{CollectionDocument, Emit};

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use bonsaidb::core::schema::{

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    Collection, CollectionMapReduce, ReduceResult, SerializedCollection, SerializedView, View,

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    ViewMapResult, ViewMappedValue, ViewSchema,

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};

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use bonsaidb::local::config::{Builder, StorageConfiguration};

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use bonsaidb::local::Database;

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use serde::{Deserialize, Serialize};

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// begin rustme snippet: snippet-a

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#[derive(Debug, Serialize, Deserialize, Collection)]

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#[collection(name = "shapes", views = [ShapesByNumberOfSides])]

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struct Shape {

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    pub sides: u32,

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#[derive(Debug, Clone, View, ViewSchema)]

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#[view(collection = Shape, key = u32, value = usize, name = "by-number-of-sides")]

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struct ShapesByNumberOfSides;

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impl CollectionMapReduce for ShapesByNumberOfSides {

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    fn map<'doc>(&self, document: CollectionDocument<Shape>) -> ViewMapResult<'doc, Self::View> {

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        document

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            .header

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            .emit_key_and_value(document.contents.sides, 1)

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    fn reduce(

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        &self,

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        mappings: &[ViewMappedValue<'_, Self>],

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        _rereduce: bool,

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    ) -> ReduceResult<Self::View> {

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        Ok(mappings.iter().map(|m| m.value).sum())

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// end rustme snippet

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fn main() -> Result<(), bonsaidb::core::Error> {

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    // begin rustme snippet: snippet-b

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    let db = Database::open::<Shape>(StorageConfiguration::new("view-examples.bonsaidb"))?;

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    // Insert a new document into the Shape collection.

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    Shape { sides: 3 }.push_into(&db)?;

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    // end rustme snippet

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    // Views in BonsaiDb are written using a Map/Reduce approach. In this

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    // example, we take a look at how document mapping can be used to filter and

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    // retrieve data

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//

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    // Let's start by seeding the database with some shapes of various sizes:

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    for sides in 3..=20 {

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        Shape { sides }.push_into(&db)?;

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    // And, let's add a few shapes with the same number of sides

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    Shape { sides: 3 }.push_into(&db)?;

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    Shape { sides: 4 }.push_into(&db)?;

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    // At this point, our database should have 3 triangles:

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    // begin rustme snippet: snippet-c

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    let triangles = ShapesByNumberOfSides::entries(&db).with_key(&3).query()?;

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    println!("Number of triangles: {}", triangles.len());

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    // end rustme snippet

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    // What is returned is a list of entries containing the document id

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    // (source), the key of the entry, and the value of the entry:

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    println!("Triangles: {triangles:#?}");

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    // If you want the associated documents, use query_with_collection_docs:

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    for entry in &ShapesByNumberOfSides::entries(&db)

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        .with_key(&3)

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        .query_with_collection_docs()?

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        println!(

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            "Shape ID {} has {} sides",

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            entry.document.header.id, entry.document.contents.sides

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);

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    // The reduce() function takes the "values" emitted during the map()

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    // function, and reduces a list down to a single value. In this example, the

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    // reduce function is acting as a count. So, if you want to query for the

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    // number of shapes, we don't need to fetch all the records, we can just

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    // retrieve the result of the calculation directly.

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//

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    // So, here we're using reduce() to count the number of shapes with 4 sides.

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    println!(

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        "Number of quads: {} (expected 2)",

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        ShapesByNumberOfSides::entries(&db).with_key(&4).reduce()?

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);

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    // Or, 5 shapes that are triangles or quads

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    println!(

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        "Number of quads and triangles: {} (expected 5)",

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        ShapesByNumberOfSides::entries(&db)

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            .with_keys(&[3, 4])

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            .reduce()?

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);

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    // And, 10 shapes that have more than 10 sides

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    println!(

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        "Number of shapes with more than 10 sides: {} (expected 10)",

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        ShapesByNumberOfSides::entries(&db)

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            .with_key_range(11..)

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            .reduce()?

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);

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    Ok(())

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#[test]

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fn runs() {

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    drop(std::fs::remove_dir_all("view-examples.bonsaidb"));

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    main().unwrap()

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