add Context::findvalues, Node::findvalues

Author: dginev

CHANGELOG.md

@@ -1,6 +1,14 @@
 # Change Log
 
-## [0.3.2] (in development)
+## [0.3.3] (in development)
+
+## [0.3.2] 2023-07-05
+
+### Added
+
+* XPath: `Context::findvalues`, with optional node-bound evaluation, obtaining `String` values.
+
+* `Node::findvalues` method for direct XPath search obtaining `String` values, without first explicitly instantiating a `Context`. Reusing a `Context` remains more efficient.
 
 ## [0.3.1] 2022-26-03
 

src/tree/node.rs

@@ -929,6 +929,12 @@ impl Node {
     context.findnodes(xpath, Some(self))
   }
 
+  /// find String values via xpath, at a specified node or the document root
+  pub fn findvalues(&self, xpath: &str) -> Result<Vec<String>, ()> {
+    let mut context = Context::from_node(self)?;
+    context.findvalues(xpath, Some(self))
+  }
+
   /// replace a `self`'s `old` child node with a `new` node in the same position
   /// borrowed from Perl's XML::LibXML
   pub fn replace_child_node(

src/xpath.rs

@@ -162,6 +162,16 @@ impl Context {
     Ok(evaluated.get_nodes_as_vec())
   }
 
+  /// find literal values via xpath, at a specified node or the document root
+  pub fn findvalues(&mut self, xpath: &str, node_opt: Option<&Node>) -> Result<Vec<String>, ()> {
+    let evaluated = if let Some(node) = node_opt {
+      self.node_evaluate(xpath, node)?
+    } else {
+      self.evaluate(xpath)?
+    };
+    Ok(evaluated.get_nodes_as_str())
+  }
+
   /// find a literal value via xpath, at a specified node or the document root
   pub fn findvalue(&mut self, xpath: &str, node_opt: Option<&Node>) -> Result<String, ()> {
     let evaluated = if let Some(node) = node_opt {
@@ -199,7 +209,7 @@ impl Object {
     v as usize
   }
 
-  /// returns the result set as a vector of node references
+  /// returns the result set as a vector of `Node` objects
   pub fn get_nodes_as_vec(&self) -> Vec<Node> {
     let n = self.get_number_of_nodes();
     let mut vec: Vec<Node> = Vec::with_capacity(n);
@@ -218,7 +228,7 @@ impl Object {
     vec
   }
 
-  /// returns the result set as a vector of node references
+  /// returns the result set as a vector of `RoNode` objects
   pub fn get_readonly_nodes_as_vec(&self) -> Vec<RoNode> {
     let n = self.get_number_of_nodes();
     let mut vec: Vec<RoNode> = Vec::with_capacity(n);
@@ -235,6 +245,31 @@ impl Object {
     }
     vec
   }
+
+  /// returns the result set as a vector of Strings
+  pub fn get_nodes_as_str(&self) -> Vec<String> {
+    let n = self.get_number_of_nodes();
+    let mut vec: Vec<String> = Vec::with_capacity(n);
+    let slice = if n > 0 {
+      xmlXPathObjectGetNodes(self.ptr, n as size_t)
+    } else {
+      Vec::new()
+    };
+    for ptr in slice {
+      if ptr.is_null() {
+        panic!("rust-libxml: xpath: found null pointer result set");
+      }
+      let value_ptr = unsafe { xmlXPathCastNodeToString(ptr) };
+      let c_value_string = unsafe { CStr::from_ptr(value_ptr as *const c_char) };
+      let ready_str = c_value_string.to_string_lossy().into_owned();
+      unsafe {
+        libc::free(value_ptr as *mut c_void);
+      }
+      vec.push(ready_str);
+    }
+    vec
+  }
+
 }
 
 impl fmt::Display for Object {

tests/resources/ids.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0"?>
+<document>
+  <test>
+    <empty/>
+  </test>
+  <test>
+    <p xml:id="start">Hello</p>
+    <deeper>
+      <p xml:id="mid"> </p>
+    </deeper>
+    <deeper>
+      <still>
+        <p xml:id="end">World!</p>
+      </still>
+    </deeper>
+  </test>
+</document>

tests/xpath_tests.rs

@@ -193,6 +193,29 @@ fn cleanup_safely_unlinked_xpath_nodes() {
   assert!(true, "Drops went OK.");
 }
 
+#[test]
+fn xpath_find_string_values() {
+  let parser = Parser::default();
+  let doc_result = parser.parse_file("tests/resources/ids.xml");
+  assert!(doc_result.is_ok());
+  let doc = doc_result.unwrap();
+  let mut xpath = libxml::xpath::Context::new(&doc).unwrap();
+  if let Some(root) = doc.get_root_element() {
+    let tests = root.get_child_elements();
+    let empty_test = &tests[0];
+    let ids_test = &tests[1];
+    let empty_values = xpath.findvalues(".//@xml:id", Some(empty_test));
+    assert_eq!(empty_values, Ok(Vec::new()));
+    let ids_values = xpath.findvalues(".//@xml:id", Some(ids_test));
+    let expected_ids = Ok(vec![String::from("start"),String::from("mid"),String::from("end")]);
+    assert_eq!(ids_values, expected_ids);
+    let node_ids_values = ids_test.findvalues(".//@xml:id");
+    assert_eq!(node_ids_values, expected_ids);
+  } else {
+    panic!("Document fails to obtain root!");
+  }
+}
+
 /// Tests for checking xpath well-formedness
 mod compile_tests {
   use libxml::xpath::is_well_formed_xpath;