Auto merge of #14096 - fflorent:11485-make-dom-methods-taking-mut-JSContent-unsafe, r=nox

11485 make dom methods taking mut js content unsafe

This is a rebased version of PR #11595

---
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #11485

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- [ ] There are tests for these changes OR
- [x] These changes do not require tests because: no code logic was changed

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components/script/dom/bindings/codegen/CodegenRust.py

@@ -2316,10 +2316,13 @@ class CGAbstractMethod(CGThing):
     arguments.
 
     docs is None or documentation for the method in a string.
+
+    unsafe is used to add the decorator 'unsafe' to a function, giving as a result
+    an 'unsafe fn()' declaration.
     """
     def __init__(self, descriptor, name, returnType, args, inline=False,
-                 alwaysInline=False, extern=False, unsafe_fn=False, pub=False,
-                 templateArgs=None, unsafe=False, docs=None, doesNotPanic=False):
+                 alwaysInline=False, extern=False, unsafe=False, pub=False,
+                 templateArgs=None, docs=None, doesNotPanic=False):
         CGThing.__init__(self)
         self.descriptor = descriptor
         self.name = name
@@ -2327,10 +2330,9 @@ class CGAbstractMethod(CGThing):
         self.args = args
         self.alwaysInline = alwaysInline
         self.extern = extern
-        self.unsafe_fn = extern or unsafe_fn
+        self.unsafe = extern or unsafe
         self.templateArgs = templateArgs
         self.pub = pub
-        self.unsafe = unsafe
         self.docs = docs
         self.catchPanic = self.extern and not doesNotPanic
 
@@ -2357,7 +2359,7 @@ class CGAbstractMethod(CGThing):
         if self.pub:
             decorators.append('pub')
 
-        if self.unsafe_fn:
+        if self.unsafe:
             decorators.append('unsafe')
 
         if self.extern:
@@ -2373,10 +2375,6 @@ class CGAbstractMethod(CGThing):
     def define(self):
         body = self.definition_body()
 
-        # Method will already be marked `unsafe` if `self.extern == True`
-        if self.unsafe and not self.extern:
-            body = CGWrapper(CGIndenter(body), pre="unsafe {\n", post="\n}")
-
         if self.catchPanic:
             body = CGWrapper(CGIndenter(body),
                              pre="return wrap_panic(|| {\n",
@@ -2409,7 +2407,7 @@ class CGConstructorEnabled(CGAbstractMethod):
                                   'ConstructorEnabled', 'bool',
                                   [Argument("*mut JSContext", "aCx"),
                                    Argument("HandleObject", "aObj")],
-                                  unsafe_fn=True)
+                                  unsafe=True)
 
     def definition_body(self):
         conditions = []
@@ -3089,7 +3087,7 @@ class CGDefineDOMInterfaceMethod(CGAbstractMethod):
             Argument('HandleObject', 'global'),
         ]
         CGAbstractMethod.__init__(self, descriptor, 'DefineDOMInterface',
-                                  'void', args, pub=True, unsafe_fn=True)
+                                  'void', args, pub=True, unsafe=True)
 
     def define(self):
         return CGAbstractMethod.define(self)
@@ -5349,10 +5347,19 @@ class CGInterfaceTrait(CGThing):
         def fmt(arguments):
             return "".join(", %s: %s" % argument for argument in arguments)
 
-        methods = [
-            CGGeneric("fn %s(&self%s) -> %s;\n" % (name, fmt(arguments), rettype))
-            for name, arguments, rettype in members()
-        ]
+        def contains_unsafe_arg(arguments):
+            if not arguments or len(arguments) == 0:
+                return False
+            return reduce((lambda x, y: x or y[1] == '*mut JSContext'), arguments, False)
+
+        methods = []
+        for name, arguments, rettype in members():
+            arguments = list(arguments)
+            methods.append(CGGeneric("%sfn %s(&self%s) -> %s;\n" % (
+                'unsafe ' if contains_unsafe_arg(arguments) else '',
+                name, fmt(arguments), rettype))
+            )
+
         if methods:
             self.cgRoot = CGWrapper(CGIndenter(CGList(methods, "")),
                                     pre="pub trait %sMethods {\n" % descriptor.interface.identifier.name,

components/script/dom/bindings/iterable.rs

@@ -85,7 +85,7 @@ impl<T: Reflectable + JSTraceable + Iterable> IterableIterator<T> {
     /// Create a new iterator instance for the provided iterable DOM interface.
     pub fn new(iterable: &T,
                type_: IteratorType,
-               wrap: fn(*mut JSContext, &GlobalScope, Box<IterableIterator<T>>)
+               wrap: unsafe fn(*mut JSContext, &GlobalScope, Box<IterableIterator<T>>)
                      -> Root<Self>) -> Root<Self> {
         let iterator = box IterableIterator {
             reflector: Reflector::new(),

components/script/dom/bindings/reflector.rs

@@ -16,12 +16,14 @@ use std::ptr;
 pub fn reflect_dom_object<T, U>(
         obj: Box<T>,
         global: &U,
-        wrap_fn: fn(*mut JSContext, &GlobalScope, Box<T>) -> Root<T>)
+        wrap_fn: unsafe fn(*mut JSContext, &GlobalScope, Box<T>) -> Root<T>)
         -> Root<T>
     where T: Reflectable, U: DerivedFrom<GlobalScope>
 {
     let global_scope = global.upcast();
-    wrap_fn(global_scope.get_cx(), global_scope, obj)
+    unsafe {
+        wrap_fn(global_scope.get_cx(), global_scope, obj)
+    }
 }
 
 /// A struct to store a reference to the reflector of a DOM object.