refactor: simplify namespace processing

BREAKING CHANGE: * The ``ns`` field is no longer using the prototype trick that sax used. The ``ns`` field of a tag contains only those namespaces that the tag declares. * We no longer have ``opennamespace`` and ``closenamespace`` events. The information they provide can be obtained by examining the tags passed to tag events.
lddubeau · Jul 23, 2018 · 2d4ce0f · 2d4ce0f
1 parent 0dab2fa
commit 2d4ce0f
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Showing 6 changed files with 34 additions and 188 deletions.
diff --git a/lib/saxes.js b/lib/saxes.js
@@ -101,8 +101,6 @@ exports.EVENTS = [
   "error",
   "end",
   "ready",
-  "opennamespace",
-  "closenamespace",
 ];
 
 const buffers = [
@@ -336,7 +334,7 @@ class SaxesParser {
     // it always points at the current tag,
     // which protos to its parent tag.
     if (this.opt.xmlns) {
-      this.ns = Object.create(rootNS);
+      this.ns = Object.assign({}, rootNS);
     }
 
     this.startTagPosition = undefined;
@@ -435,26 +433,6 @@ class SaxesParser {
    */
   onready() {}
 
-  /**
-   * Event handler indicating that a new namespace binding is effective. This
-   * is called only when namespaces are tracked. The default implementation is
-   * a no-op.
-   *
-   * @param {{prefix: string, uri: string}} binding The prefix being bound and
-   * the URI bound to it.
-   */
-  onopennamespace() {}
-
-  /**
-   * Event handler indicating that a new namespace binding is no longer
-   * effective. This is called only when namespaces are tracked. The default
-   * implementation is a no-op.
-   *
-   * @param {{prefix: string, uri: string}} binding The prefix being
-   * unbound and the URI bound to it.
-   */
-  onclosenamespace() {}
-
   /**
    * Event handler indicating an error. The default implementation throws the
    * error. Override with a no-op handler if you don't want this.
@@ -1320,16 +1298,15 @@ class SaxesParser {
       return;
     }
 
-    const parent = this.tags[this.tags.length - 1] || this;
     const tag = this.tag = {
       name: this.tagName,
       attributes: Object.create(null),
     };
 
-    // will be overridden if tag contails an xmlns="foo" or xmlns:foo="bar"
     if (this.opt.xmlns) {
-      tag.ns = parent.ns;
+      tag.ns = Object.create(null);
     }
+
     this.attribList = [];
     this.emitNode("onopentagstart", tag);
 
@@ -1652,6 +1629,21 @@ class SaxesParser {
     this[nodeType](data);
   }
 
+  _resolve(prefix, index) {
+    if (index < 0) {
+      return this.ns[prefix];
+    }
+
+    const uri = this.tags[index].ns[prefix];
+    return uri !== undefined ? uri : this._resolve(prefix, index - 1);
+  }
+
+  resolve(prefix) {
+    const uri = this.tag.ns[prefix];
+    return uri !== undefined ? uri :
+      this._resolve(prefix, this.tags.length - 1);
+  }
+
   /**
    * Parse a qname into its prefix and local name parts.
    *
@@ -1693,7 +1685,7 @@ class SaxesParser {
   /**
    * Handle a complete open tag. This parser code calls this once it has seen
    * the whole tag. This method checks for well-formeness and then emits
-   * ``onopentag``. It also emits any necessary ``onopennamespace``.
+   * ``onopentag``.
    *
    * @param {boolean} [selfClosing=false] Whether the tag is self-closing.
    *
@@ -1703,10 +1695,7 @@ class SaxesParser {
     const { tag } = this;
     if (this.opt.xmlns) {
       // emit namespace binding events
-      const parent = this.tags[this.tags.length - 1] || this;
-
-      let { ns } = tag;
-      let disconnectedNS = false;
+      const { ns } = tag;
       // eslint-disable-next-line prefer-const
       for (let [name, uri] of this.attribList) {
         const { prefix, local } = this.qname(name, true);
@@ -1744,12 +1733,7 @@ ${XML_NAMESPACE}.`);
             default:
             }
 
-            if (!disconnectedNS) {
-              ns = tag.ns = Object.create(parent.ns);
-              disconnectedNS = true;
-            }
             ns[local] = uri;
-            this.emitNode("onopennamespace", { prefix: local, uri });
           }
         }
       }
@@ -1758,7 +1742,7 @@ ${XML_NAMESPACE}.`);
       const qn = this.qname(this.tagName);
       tag.prefix = qn.prefix;
       tag.local = qn.local;
-      tag.uri = ns[qn.prefix] || "";
+      tag.uri = this.resolve(qn.prefix) || "";
 
       if (tag.prefix) {
         if (tag.prefix === "xmlns") {
@@ -1777,7 +1761,7 @@ ${JSON.stringify(this.tagName)}.`);
       //   http://www.w3.org/TR/REC-xml-names/#defaulting
       for (const [name, value] of this.attribList) {
         const { prefix, local } = this.qname(name, true);
-        const uri = prefix === "" ? "" : (ns[prefix] || "");
+        const uri = prefix === "" ? "" : (this.resolve(prefix) || "");
         const a = {
           name,
           value,
@@ -1835,7 +1819,7 @@ ${JSON.stringify(this.tagName)}.`);
   /**
    * Handle a complete close tag. This parser code calls this once it has seen
    * the whole tag. This method checks for well-formeness and then emits
-   * ``onclosetag``. It also emits any necessary ``onclosenamespace``.
+   * ``onclosetag``.
    *
    * @private
    */
@@ -1873,14 +1857,6 @@ ${JSON.stringify(this.tagName)}.`);
     while (s-- > t) {
       const tag = this.tag = tags.pop();
       this.emitNode("onclosetag", tag.name);
-
-      const parent = tags[tags.length - 1] || this;
-      if (this.opt.xmlns && tag.ns !== parent.ns) {
-        // remove namespace bindings introduced by tag
-        for (const p of Object.keys(tag.ns)) {
-          this.emitNode("onclosenamespace", { prefix: p, uri: tag.ns[p] });
-        }
-      }
     }
     if (t === 0) {
       this.inRoot = false;

diff --git a/test/xmlns-issue-41.js b/test/xmlns-issue-41.js
@@ -4,13 +4,6 @@ const t = require(".");
 
 const expect = [
   ["opentagstart", { name: "parent", attributes: {}, ns: {} }],
-  [
-    "opennamespace",
-    {
-      prefix: "a",
-      uri: "http://ATTRIBUTE",
-    },
-  ],
   [
     "opentag",
     {
@@ -44,13 +37,6 @@ const expect = [
     "closetag",
     "parent",
   ],
-  [
-    "closenamespace",
-    {
-      prefix: "a",
-      uri: "http://ATTRIBUTE",
-    },
-  ],
 ];
 
 // should be the same both ways.

diff --git a/test/xmlns-rebinding.js b/test/xmlns-rebinding.js
@@ -17,20 +17,6 @@ require(".").test({
         ns: {},
       },
     ],
-    [
-      "opennamespace",
-      {
-        prefix: "x",
-        uri: "x1",
-      },
-    ],
-    [
-      "opennamespace",
-      {
-        prefix: "y",
-        uri: "y1",
-      },
-    ],
     [
       "opentag",
       {
@@ -80,17 +66,7 @@ require(".").test({
       {
         name: "rebind",
         attributes: {},
-        ns: {
-          x: "x1",
-          y: "y1",
-        },
-      },
-    ],
-    [
-      "opennamespace",
-      {
-        prefix: "x",
-        uri: "x2",
+        ns: {},
       },
     ],
     [
@@ -120,9 +96,7 @@ require(".").test({
       {
         name: "check",
         attributes: {},
-        ns: {
-          x: "x2",
-        },
+        ns: {},
       },
     ],
     [
@@ -148,9 +122,7 @@ require(".").test({
             local: "a",
           },
         },
-        ns: {
-          x: "x2",
-        },
+        ns: {},
         isSelfClosing: true,
       },
     ],
@@ -162,22 +134,12 @@ require(".").test({
       "closetag",
       "rebind",
     ],
-    [
-      "closenamespace",
-      {
-        prefix: "x",
-        uri: "x2",
-      },
-    ],
     [
       "opentagstart",
       {
         name: "check",
         attributes: {},
-        ns: {
-          x: "x1",
-          y: "y1",
-        },
+        ns: {},
       },
     ],
     [
@@ -203,10 +165,7 @@ require(".").test({
             local: "a",
           },
         },
-        ns: {
-          x: "x1",
-          y: "y1",
-        },
+        ns: {},
         isSelfClosing: true,
       },
     ],
@@ -218,20 +177,6 @@ require(".").test({
       "closetag",
       "root",
     ],
-    [
-      "closenamespace",
-      {
-        prefix: "x",
-        uri: "x1",
-      },
-    ],
-    [
-      "closenamespace",
-      {
-        prefix: "y",
-        uri: "y1",
-      },
-    ],
   ],
   opt: {
     xmlns: true,