Vendor things

third-party/vendor/toml_edit/examples/visit.rs

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+//! Example for how to use `VisitMut` to iterate over a table.
+
+use std::collections::BTreeSet;
+use toml_edit::visit::*;
+use toml_edit::visit_mut::*;
+use toml_edit::{Array, Document, InlineTable, Item, KeyMut, Table, Value};
+
+/// This models the visit state for dependency keys in a `Cargo.toml`.
+///
+/// Dependencies can be specified as:
+///
+/// ```toml
+/// [dependencies]
+/// dep1 = "0.2"
+///
+/// [build-dependencies]
+/// dep2 = "0.3"
+///
+/// [dev-dependencies]
+/// dep3 = "0.4"
+///
+/// [target.'cfg(windows)'.dependencies]
+/// dep4 = "0.5"
+///
+/// # and target build- and dev-dependencies
+/// ```
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+enum VisitState {
+    /// Represents the root of the table.
+    Root,
+    /// Represents "dependencies", "build-dependencies" or "dev-dependencies", or the target
+    /// forms of these.
+    Dependencies,
+    /// A table within dependencies.
+    SubDependencies,
+    /// Represents "target".
+    Target,
+    /// "target.[TARGET]".
+    TargetWithSpec,
+    /// Represents some other state.
+    Other,
+}
+
+impl VisitState {
+    /// Figures out the next visit state, given the current state and the given key.
+    fn descend(self, key: &str) -> Self {
+        match (self, key) {
+            (
+                VisitState::Root | VisitState::TargetWithSpec,
+                "dependencies" | "build-dependencies" | "dev-dependencies",
+            ) => VisitState::Dependencies,
+            (VisitState::Root, "target") => VisitState::Target,
+            (VisitState::Root | VisitState::TargetWithSpec, _) => VisitState::Other,
+            (VisitState::Target, _) => VisitState::TargetWithSpec,
+            (VisitState::Dependencies, _) => VisitState::SubDependencies,
+            (VisitState::SubDependencies, _) => VisitState::SubDependencies,
+            (VisitState::Other, _) => VisitState::Other,
+        }
+    }
+}
+
+/// Collect the names of every dependency key.
+#[derive(Debug)]
+struct DependencyNameVisitor<'doc> {
+    state: VisitState,
+    names: BTreeSet<&'doc str>,
+}
+
+impl<'doc> Visit<'doc> for DependencyNameVisitor<'doc> {
+    fn visit_table_like_kv(&mut self, key: &'doc str, node: &'doc Item) {
+        if self.state == VisitState::Dependencies {
+            self.names.insert(key);
+        } else {
+            // Since we're only interested in collecting the top-level keys right under
+            // [dependencies], don't recurse unconditionally.
+
+            let old_state = self.state;
+
+            // Figure out the next state given the key.
+            self.state = self.state.descend(key);
+
+            // Recurse further into the document tree.
+            visit_table_like_kv(self, key, node);
+
+            // Restore the old state after it's done.
+            self.state = old_state;
+        }
+    }
+}
+
+/// Normalize all dependency tables into the format:
+///
+/// ```toml
+/// [dependencies]
+/// dep = { version = "1.0", features = ["foo", "bar"], ... }
+/// ```
+///
+/// leaving other tables untouched.
+#[derive(Debug)]
+struct NormalizeDependencyTablesVisitor {
+    state: VisitState,
+}
+
+impl VisitMut for NormalizeDependencyTablesVisitor {
+    fn visit_table_mut(&mut self, node: &mut Table) {
+        visit_table_mut(self, node);
+
+        // The conversion from regular tables into inline ones might leave some explicit parent
+        // tables hanging, so convert them to implicit.
+        if matches!(self.state, VisitState::Target | VisitState::TargetWithSpec) {
+            node.set_implicit(true);
+        }
+    }
+
+    fn visit_table_like_kv_mut(&mut self, mut key: KeyMut<'_>, node: &mut Item) {
+        let old_state = self.state;
+
+        // Figure out the next state given the key.
+        self.state = self.state.descend(key.get());
+
+        match self.state {
+            VisitState::Target | VisitState::TargetWithSpec | VisitState::Dependencies => {
+                // Top-level dependency row, or above: turn inline tables into regular ones.
+                if let Item::Value(Value::InlineTable(inline_table)) = node {
+                    let inline_table = std::mem::replace(inline_table, InlineTable::new());
+                    let table = inline_table.into_table();
+                    key.fmt();
+                    *node = Item::Table(table);
+                }
+            }
+            VisitState::SubDependencies => {
+                // Individual dependency: turn regular tables into inline ones.
+                if let Item::Table(table) = node {
+                    // Turn the table into an inline table.
+                    let table = std::mem::replace(table, Table::new());
+                    let inline_table = table.into_inline_table();
+                    key.fmt();
+                    *node = Item::Value(Value::InlineTable(inline_table));
+                }
+            }
+            _ => {}
+        }
+
+        // Recurse further into the document tree.
+        visit_table_like_kv_mut(self, key, node);
+
+        // Restore the old state after it's done.
+        self.state = old_state;
+    }
+
+    fn visit_array_mut(&mut self, node: &mut Array) {
+        // Format any arrays within dependencies to be on the same line.
+        if matches!(
+            self.state,
+            VisitState::Dependencies | VisitState::SubDependencies
+        ) {
+            node.fmt();
+        }
+    }
+}
+
+/// This is the input provided to visit_mut_example.
+static INPUT: &str = r#"
+[package]
+name = "my-package"
+
+[package.metadata.foo]
+bar = 42
+
+[dependencies]
+atty = "0.2"
+cargo-platform = { path = "crates/cargo-platform", version = "0.1.2" }
+
+[dependencies.pretty_env_logger]
+version = "0.4"
+optional = true
+
+[target.'cfg(windows)'.dependencies]
+fwdansi = "1.1.0"
+
+[target.'cfg(windows)'.dependencies.winapi]
+version = "0.3"
+features = [
+"handleapi",
+"jobapi",
+]
+
+[target.'cfg(unix)']
+dev-dependencies = { miniz_oxide = "0.5" }
+
+[dev-dependencies.cargo-test-macro]
+path = "crates/cargo-test-macro"
+
+[build-dependencies.flate2]
+version = "0.4"
+"#;
+
+/// This is the output produced by visit_mut_example.
+#[cfg(test)]
+static VISIT_MUT_OUTPUT: &str = r#"
+[package]
+name = "my-package"
+
+[package.metadata.foo]
+bar = 42
+
+[dependencies]
+atty = "0.2"
+cargo-platform = { path = "crates/cargo-platform", version = "0.1.2" }
+pretty_env_logger = { version = "0.4", optional = true }
+
+[target.'cfg(windows)'.dependencies]
+fwdansi = "1.1.0"
+winapi = { version = "0.3", features = ["handleapi", "jobapi"] }
+
+[target.'cfg(unix)'.dev-dependencies]
+miniz_oxide = "0.5"
+
+[dev-dependencies]
+cargo-test-macro = { path = "crates/cargo-test-macro" }
+
+[build-dependencies]
+flate2 = { version = "0.4" }
+"#;
+
+fn visit_example(document: &Document) -> BTreeSet<&str> {
+    let mut visitor = DependencyNameVisitor {
+        state: VisitState::Root,
+        names: BTreeSet::new(),
+    };
+
+    visitor.visit_document(document);
+
+    visitor.names
+}
+
+fn visit_mut_example(document: &mut Document) {
+    let mut visitor = NormalizeDependencyTablesVisitor {
+        state: VisitState::Root,
+    };
+
+    visitor.visit_document_mut(document);
+}
+
+fn main() {
+    let mut document: Document = INPUT.parse().expect("input is valid TOML");
+
+    println!("** visit example");
+    println!("{:?}", visit_example(&document));
+
+    println!("** visit_mut example");
+    visit_mut_example(&mut document);
+    println!("{}", document);
+}
+
+#[cfg(test)]
+#[test]
+fn visit_correct() {
+    let document: Document = INPUT.parse().expect("input is valid TOML");
+
+    let names = visit_example(&document);
+    let expected = vec![
+        "atty",
+        "cargo-platform",
+        "pretty_env_logger",
+        "fwdansi",
+        "winapi",
+        "miniz_oxide",
+        "cargo-test-macro",
+        "flate2",
+    ]
+    .into_iter()
+    .collect();
+    assert_eq!(names, expected);
+}
+
+#[cfg(test)]
+#[test]
+fn visit_mut_correct() {
+    let mut document: Document = INPUT.parse().expect("input is valid TOML");
+
+    visit_mut_example(&mut document);
+    assert_eq!(format!("{}", document), VISIT_MUT_OUTPUT);
+}