jengebr commented on code in PR #842:
URL: https://github.com/apache/tomcat/pull/842#discussion_r2046881926
##########
java/org/apache/jasper/compiler/Generator.java:
##########
@@ -3028,6 +3036,195 @@ public String
generateNamedAttributeJspFragment(Node.NamedAttribute n, String ta
return varName;
}
+
+ /**
+ * Determines whether a tag should be handled via nonstandard code
(typically
+ * faster). Considers both configuration and level of support within
Tomcat.
+ *
+ * Note that Tomcat is free to ignore any case it cannot handle, as
long as it
+ * reports it accurately to the caller by returning false. For
example, the
+ * initial implementation for c:set excludes support for body content.
c:set
+ * tags with body content will be generated with the standard code and
tags
+ * without body content will be generated via non-standard code.
+ *
+ * @param n
+ * @param jspAttributes
+ * @return whether code was generated
+ * @throws JasperException
+ */
+ private boolean visitPotentiallyNonstandardCustomTag(Node.CustomTag n)
+ throws JasperException {
+ if (!nonstandardCustomTagNames.contains(n.getQName())) {
+ // tag is not configured, move along
+ return false;
+ }
+
+ Map<String, JspAttribute> jspAttributes = new HashMap<>();
+ if (n.getJspAttributes() != null) {
+ for (JspAttribute jspAttr : n.getJspAttributes()) {
+ jspAttributes.put(jspAttr.getLocalName(), jspAttr);
+ }
+ }
+ switch (n.qName) {
+ case "c:set":
+ // requires var and value, scope is optional, body is
prohibited, value cannot be deferred
+ if (n.hasEmptyBody()
+ && jspAttributes.containsKey("var")
+ && jspAttributes.containsKey("value")
+ && CORE_LIBS_URI.equals(n.getURI())) {
+ // verify value is not a deferred expression
+ String valueText = jspAttributes.get("value").getValue();
+ if (valueText.startsWith("#")) {
+ return false;
+ } else if (jspAttributes.size() == 2
+ || (jspAttributes.size() == 3 &&
jspAttributes.containsKey("scope"))) {
+ generateNonstandardSetLogic(n, jspAttributes);
+ return true;
+ }
+ }
+ break;
+ case "c:remove":
+ // requires var, scope is optional, body is prohibited
+ if (n.hasEmptyBody()
+ && jspAttributes.containsKey("var")
+ && CORE_LIBS_URI.equals(n.getURI())
+ && (jspAttributes.size() == 1
+ || (jspAttributes.size() == 2
+ && jspAttributes.containsKey("scope")))) {
+ generateNonstandardRemoveLogic(n, jspAttributes);
+ return true;
+
+ }
+ break;
+ default:
+ // This indicates someone configured a tag with no
non-standard implementation.
+ // Harmless.
+ }
+ return false;
+ }
+
+ private void generateNonstandardSetLogic(Node.CustomTag n, Map<String,
JspAttribute> jspAttributes)
+ throws JasperException {
+ String baseVar = createTagVarName(n.getQName(), n.getPrefix(),
n.getLocalName());
+ String tagMethod = "_jspx_meth_" + baseVar;
+ ServletWriter outSave = out;
+
+ // generate method call
+ out.printin(tagMethod);
+ out.print("(");
+ out.print("_jspx_page_context");
+ out.println(");");
+ GenBuffer genBuffer = new GenBuffer(n, n.getBody());
+ methodsBuffered.add(genBuffer);
+ out = genBuffer.getOut();
+
+ // Generate code for method declaration
+ methodNesting++;
+ out.println();
+ out.pushIndent();
+ out.printin("private void ");
+ out.print(tagMethod);
+ out.println("(jakarta.servlet.jsp.PageContext
_jspx_page_context)");
+ out.printil(" throws java.lang.Throwable {");
+ out.pushIndent();
+ // Generated body of method
+ out.printil("// " + n.getQName());
+
+ JspAttribute varAttribute = jspAttributes.get("var");
+ Mark m = n.getStart();
+ out.printil("// " + m.getFile() + "(" + m.getLineNumber() + "," +
m.getColumnNumber() + ") "
+ + varAttribute.getTagAttributeInfo());
+
+ JspAttribute valueAttribute = jspAttributes.get("value");
+ m = n.getStart();
+ out.printil("// " + m.getFile() + "(" + m.getLineNumber() + "," +
m.getColumnNumber() + ") "
+ + valueAttribute.getTagAttributeInfo());
+
+ String varValue = varAttribute.getValue();
+ String scopeValue = translateScopeToConstant(jspAttributes);
+ String evaluatedAttribute =
evaluateAttribute(getTagHandlerInfo(n), valueAttribute,
+ n, null);
+
out.printil("org.apache.jasper.runtime.JspRuntimeLibrary.nonstandardSetTag(_jspx_page_context,
\""
+ + varValue + "\", " + evaluatedAttribute + ", " +
scopeValue + ");");
+ // Generate end of method
+ out.popIndent();
+ out.printil("}");
+ out.popIndent();
+
+ methodNesting--;
+ // restore previous writer
+ out = outSave;
+ }
+
+ private String translateScopeToConstant(Map<String, JspAttribute>
jspAttributes) {
+ String scopeValue;
+ JspAttribute scopeAttribute = jspAttributes.get("scope");
+ if (scopeAttribute == null) {
+ scopeValue = "jakarta.servlet.jsp.PageContext.PAGE_SCOPE";
+ } else {
+ switch (scopeAttribute.getValue()) {
+ case "":
+ case "page":
+ scopeValue = "jakarta.servlet.jsp.PageContext.PAGE_SCOPE";
+ break;
+ case "request":
+ scopeValue =
"jakarta.servlet.jsp.PageContext.REQUEST_SCOPE";
+ break;
+ case "session":
+ scopeValue =
"jakarta.servlet.jsp.PageContext.SESSION_SCOPE";
+ break;
+ case "application":
+ scopeValue =
"jakarta.servlet.jsp.PageContext.APPLICATION_SCOPE";
+ break;
+ default:
+ throw new
IllegalArgumentException(Localizer.getMessage("jsp.error.page.invalid.scope"));
+ }
+ }
+ return scopeValue;
+ }
+
+ private void generateNonstandardRemoveLogic(Node.CustomTag n,
Map<String, JspAttribute> jspAttributes)
+ throws JasperException {
+ String baseVar = createTagVarName(n.getQName(), n.getPrefix(),
n.getLocalName());
+ String tagMethod = "_jspx_meth_" + baseVar;
+ ServletWriter outSave = out;
+
+ // generate method call
+ out.printin(tagMethod);
+ out.print("(");
+ out.print("_jspx_page_context");
+ out.println(");");
+ GenBuffer genBuffer = new GenBuffer(n, n.getBody());
+ methodsBuffered.add(genBuffer);
+ out = genBuffer.getOut();
+
+ // Generate code for method declaration
+ methodNesting++;
+ out.println();
+ out.pushIndent();
+ out.printin("private void ");
+ out.print(tagMethod);
+ out.println("(jakarta.servlet.jsp.PageContext pageContext)");
+ out.printil(" throws java.lang.Throwable {");
+ out.pushIndent();
+ // Generated body of method
+ String varValue = jspAttributes.get("var").getValue();
+ JspAttribute scope = jspAttributes.get("scope");
+ if (scope == null) {
+ out.printil("pageContext.removeAttribute(\"" + varValue +
"\");");
+ } else {
+ String scopeValue = translateScopeToConstant(jspAttributes);
+ out.printil("pageContext.removeAttribute(\"" + varValue + "\",
" + scopeValue + ");");
+ }
Review Comment:
Weird as this is, I think it matches the logic from
[RemoveTag](https://github.com/javaee/jstl-api/blob/master/impl/src/main/java/org/apache/taglibs/standard/tag/common/core/RemoveTag.java):
```
// removes the variable (from a specific scope, if specified)
public int doEndTag() throws JspException {
if (!scopeSpecified)
pageContext.removeAttribute(var);
else
pageContext.removeAttribute(var, scope);
return EVAL_PAGE;
}
```
And PageContextImpl .remove(var) removes from every scope, whereas
.remove(var, scope) only removes from one:.
```
@Override
public void removeAttribute(final String name) {
if (name == null) {
throw new
NullPointerException(Localizer.getMessage("jsp.error.attribute.null_name"));
}
removeAttribute(name, PAGE_SCOPE);
removeAttribute(name, REQUEST_SCOPE);
if (session != null) {
try {
removeAttribute(name, SESSION_SCOPE);
} catch (IllegalStateException ise) {
// Session has been invalidated.
// Ignore and fall throw to application scope.
}
}
removeAttribute(name, APPLICATION_SCOPE);
}
```
Until this effort, I didn't know that remove w/o scope cleared all scopes.
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