Example #1
0
// escapeTemplateBody escapes the given template assuming the given output
// context, and returns the best guess at the output context and whether the
// assumption was correct.
func (e *escaper) escapeTemplateBody(c context, t *template.Template) (context, bool) {
	filter := func(e1 *escaper, c1 context) bool {
		if c1.state == stateError {
			// Do not update the input escaper, e.
			return false
		}
		if !e1.called[t.Name()] {
			// If t is not recursively called, then c1 is an
			// accurate output context.
			return true
		}
		// c1 is accurate if it matches our assumed output context.
		return c.eq(c1)
	}
	// We need to assume an output context so that recursive template calls
	// take the fast path out of escapeTree instead of infinitely recursing.
	// Naively assuming that the input context is the same as the output
	// works >90% of the time.
	e.output[t.Name()] = c
	return e.escapeListConditionally(c, t.Tree.Root, filter)
}
Example #2
0
// computeOutCtx takes a template and its start context and computes the output
// context while storing any inferences in e.
func (e *escaper) computeOutCtx(c context, t *template.Template) context {
	// Propagate context over the body.
	c1, ok := e.escapeTemplateBody(c, t)
	if !ok {
		// Look for a fixed point by assuming c1 as the output context.
		if c2, ok2 := e.escapeTemplateBody(c1, t); ok2 {
			c1, ok = c2, true
		}
		// Use c1 as the error context if neither assumption worked.
	}
	if !ok && c1.state != stateError {
		return context{
			state: stateError,
			err:   errorf(ErrOutputContext, t.Tree.Root, 0, "cannot compute output context for template %s", t.Name()),
		}
	}
	return c1
}