mojo: Add maps to java bindings.

BUG=413863
R=ppi@chromium.org,erg@chromium.org

Review URL: https://codereview.chromium.org/648683003

Cr-Commit-Position: refs/heads/master@{#299295}

mojo/public/java/bindings/src/org/chromium/mojo/bindings/BindingsHelper.java

@@ -4,6 +4,7 @@
 
 package org.chromium.mojo.bindings;
 
+import org.chromium.mojo.bindings.Struct.DataHeader;
 import org.chromium.mojo.system.AsyncWaiter;
 import org.chromium.mojo.system.Handle;
 
@@ -29,16 +30,14 @@ public class BindingsHelper {
     public static final int POINTER_SIZE = 8;
 
     /**
-     * The value used for the expected length of a non-fixed size array.
+     * The header for a serialized map element.
      */
-    public static final int UNSPECIFIED_ARRAY_LENGTH = -1;
+    public static final DataHeader MAP_STRUCT_HEADER = new DataHeader(24, 2);
 
     /**
-     * Align |size| on {@link BindingsHelper#ALIGNMENT}.
+     * The value used for the expected length of a non-fixed size array.
      */
-    public static int align(int size) {
-        return (size + ALIGNMENT - 1) & ~(ALIGNMENT - 1);
-    }
+    public static final int UNSPECIFIED_ARRAY_LENGTH = -1;
 
     /**
      * Passed as |arrayNullability| when neither the array nor its elements are nullable.
@@ -63,6 +62,13 @@ public class BindingsHelper {
         return (arrayNullability & ELEMENT_NULLABLE) > 0;
     }
 
+    /**
+     * Align |size| on {@link BindingsHelper#ALIGNMENT}.
+     */
+    public static int align(int size) {
+        return (size + ALIGNMENT - 1) & ~(ALIGNMENT - 1);
+    }
+
     /**
      * Align |size| on {@link BindingsHelper#ALIGNMENT}.
      */

mojo/public/java/bindings/src/org/chromium/mojo/bindings/Decoder.java

@@ -144,6 +144,21 @@ public class Decoder {
         return readDataHeaderForArray(8, expectedLength);
     }
 
+    /**
+     * Deserializes a {@link DataHeader} at the given offset and checks if it is correct for a map.
+     */
+    public void readDataHeaderForMap() {
+        DataHeader si = readDataHeader();
+        if (si.size != BindingsHelper.MAP_STRUCT_HEADER.size) {
+            throw new DeserializationException(
+                    "Incorrect header for map. The size is incorrect.");
+        }
+        if (si.numFields != BindingsHelper.MAP_STRUCT_HEADER.numFields) {
+            throw new DeserializationException(
+                    "Incorrect header for map. The number of fields is incorrect.");
+        }
+    }
+
     /**
      * Deserializes a byte at the given offset.
      */

mojo/public/java/bindings/src/org/chromium/mojo/bindings/Encoder.java

@@ -422,6 +422,11 @@ public class Encoder {
         }
     }
 
+    public Encoder encoderForMap(int offset) {
+        encodePointerToNextUnclaimedData(offset);
+        return getEncoderAtDataOffset(BindingsHelper.MAP_STRUCT_HEADER);
+    }
+
     /**
      * Encodes an array of {@link InterfaceRequest}.
      */

mojo/public/tools/bindings/generators/java_templates/struct_definition.tmpl

 {% from "constant_definition.tmpl" import constant_def %}
 {% from "enum_definition.tmpl" import enum_def %}
 
-{%- macro array_expected_length(kind) -%}
-{%- if kind|is_fixed_array_kind -%}
-{{kind.length}}
-{%- else -%}
-org.chromium.mojo.bindings.BindingsHelper.UNSPECIFIED_ARRAY_LENGTH
-{%- endif -%}
-{%- endmacro -%}
-
 {% macro encode(variable, kind, offset, bit, level=0) %}
 {% if kind|is_pointer_array_kind %}
 {% set sub_kind = kind.kind %}
 if ({{variable}} == null) {
     encoder{{level}}.encodeNullPointer({{offset}}, {{kind|is_nullable_kind|java_true_false}});
 } else {
-    org.chromium.mojo.bindings.Encoder encoder{{level + 1}} = encoder{{level}}.encodePointerArray({{variable}}.length, {{offset}}, {{array_expected_length(kind)}});
+    org.chromium.mojo.bindings.Encoder encoder{{level + 1}} = encoder{{level}}.encodePointerArray({{variable}}.length, {{offset}}, {{kind|array_expected_length}});
     for (int i{{level}} = 0; i{{level}} < {{variable}}.length; ++i{{level}}) {
         {{encode(variable~'[i'~level~']', sub_kind, 'DataHeader.HEADER_SIZE + org.chromium.mojo.bindings.BindingsHelper.POINTER_SIZE * i'~level, 0, level+1)|indent(8)}}
     }
 }
+{% elif kind|is_map_kind %}
+if ({{variable}} == null) {
+    encoder{{level}}.encodeNullPointer({{offset}}, {{kind|is_nullable_kind|java_true_false}});
+} else {
+    org.chromium.mojo.bindings.Encoder encoder{{level + 1}} = encoder{{level}}.encoderForMap({{offset}});
+    int size{{level}} = {{variable}}.size();
+    {{kind.key_kind|java_type}}[] keys{{level}} = {{kind.key_kind|array|new_array('size'~level)}};
+    {{kind.value_kind|java_type}}[] values{{level}} = {{kind.value_kind|array|new_array('size'~level)}};
+    int index{{level}} = 0;
+    for (java.util.Map.Entry<{{kind.key_kind|java_type(true)}}, {{kind.value_kind|java_type(true)}}> entry{{level}} : {{variable}}.entrySet()) {
+        keys{{level}}[index{{level}}] = entry{{level}}.getKey();
+        values{{level}}[index{{level}}] = entry{{level}}.getValue();
+    }
+    {{encode('keys'~level, kind.key_kind|array, 'DataHeader.HEADER_SIZE', 0, level+1)|indent(4)}}
+    {{encode('values'~level, kind.value_kind|array, 'DataHeader.HEADER_SIZE + org.chromium.mojo.bindings.BindingsHelper.POINTER_SIZE', 0, level+1)|indent(4)}}
+}
 {% else %}
 encoder{{level}}.{{kind|encode_method(variable, offset, bit)}};
 {% endif %}
 {% endmacro %}
 
 {% macro decode(variable, kind, offset, bit, level=0) %}
-{% if kind|is_struct_kind or kind|is_pointer_array_kind %}
+{% if kind|is_struct_kind or kind|is_pointer_array_kind or kind|is_map_kind %}
 org.chromium.mojo.bindings.Decoder decoder{{level+1}} = decoder{{level}}.readPointer({{offset}}, {{kind|is_nullable_kind|java_true_false}});
 {%   if kind|is_struct_kind %}
 {{variable}} = {{kind|java_type}}.decode(decoder{{level+1}});
-{%   else %}{# kind|is_pointer_array_kind #}
+{%   else %}{# kind|is_pointer_array_kind or is_map_kind #}
 if (decoder{{level+1}} == null) {
     {{variable}} = null;
 } else {
-    DataHeader si{{level+1}} = decoder{{level+1}}.readDataHeaderForPointerArray({{array_expected_length(kind)}});
+{%     if kind|is_map_kind %}
+    decoder{{level+1}}.readDataHeaderForMap();
+    {{kind.key_kind|java_type}}[] keys{{level}};
+    {{kind.value_kind|java_type}}[] values{{level}};
+    {
+        {{decode('keys'~level, kind.key_kind|array, 'DataHeader.HEADER_SIZE', 0, level+1)|indent(8)}}
+    }
+    {
+        {{decode('values'~level, kind.value_kind|array('keys'~level~'.length'), 'DataHeader.HEADER_SIZE + org.chromium.mojo.bindings.BindingsHelper.POINTER_SIZE', 0, level+1)|indent(8)}}
+    }
+    {{variable}} = new java.util.HashMap<{{kind.key_kind|java_type(true)}}, {{kind.value_kind|java_type(true)}}>();
+    for (int index{{level}} = 0; index{{level}} < keys{{level}}.length; ++index{{level}}) {
+        {{variable}}.put(keys{{level}}[index{{level}}],  values{{level}}[index{{level}}]);
+    }
+{%     else %}
+    DataHeader si{{level+1}} = decoder{{level+1}}.readDataHeaderForPointerArray({{kind|array_expected_length}});
     {{variable}} = {{kind|new_array('si'~(level+1)~'.numFields')}};
     for (int i{{level+1}} = 0; i{{level+1}} < si{{level+1}}.numFields; ++i{{level+1}}) {
         {{decode(variable~'[i'~(level+1)~']', kind.kind, 'DataHeader.HEADER_SIZE + org.chromium.mojo.bindings.BindingsHelper.POINTER_SIZE * i'~(level+1), 0, level+1)|indent(8)}}
     }
+{%     endif %}
 }
 {%   endif %}
 {% else %}

mojo/public/tools/bindings/generators/mojom_java_generator.py

@@ -181,11 +181,7 @@ def AppendEncodeDecodeParams(initial_params, context, kind, bit):
     else:
       params.append(GetJavaTrueFalse(mojom.IsNullableKind(kind)))
   if mojom.IsAnyArrayKind(kind):
-    if mojom.IsFixedArrayKind(kind):
-      params.append(str(kind.length))
-    else:
-      params.append(
-        'org.chromium.mojo.bindings.BindingsHelper.UNSPECIFIED_ARRAY_LENGTH');
+    params.append(GetArrayExpectedLength(kind))
   if mojom.IsInterfaceKind(kind):
     params.append('%s.MANAGER' % GetJavaType(context, kind))
   if mojom.IsAnyArrayKind(kind) and mojom.IsInterfaceKind(kind.kind):
@@ -253,6 +249,10 @@ def GetJavaType(context, kind, boxed=False):
   if mojom.IsInterfaceRequestKind(kind):
     return ('org.chromium.mojo.bindings.InterfaceRequest<%s>' %
             GetNameForKind(context, kind.kind))
+  if mojom.IsMapKind(kind):
+    return 'java.util.Map<%s, %s>' % (
+        GetBoxedJavaType(context, kind.key_kind),
+        GetBoxedJavaType(context, kind.value_kind))
   if mojom.IsAnyArrayKind(kind):
     return '%s[]' % GetJavaType(context, kind.kind)
   if mojom.IsEnumKind(kind):
@@ -323,6 +323,20 @@ def ExpressionToText(context, token, kind_spec=''):
       return 'java.lang.Float.NaN'
   return token
 
+def GetArrayKind(kind, size = None):
+  if size is None:
+    return mojom.Array(kind)
+  else:
+    array = mojom.FixedArray(0, kind)
+    array.java_map_size = size
+    return array
+
+def GetArrayExpectedLength(kind):
+  if mojom.IsFixedArrayKind(kind):
+    return getattr(kind, 'java_map_size', str(kind.length))
+  else:
+    return 'org.chromium.mojo.bindings.BindingsHelper.UNSPECIFIED_ARRAY_LENGTH'
+
 def IsPointerArrayKind(kind):
   if not mojom.IsAnyArrayKind(kind):
     return False
@@ -379,6 +393,8 @@ def ZipContentInto(root, zip_filename):
 class Generator(generator.Generator):
 
   java_filters = {
+    'array': GetArrayKind,
+    'array_expected_length': GetArrayExpectedLength,
     'interface_response_name': GetInterfaceResponseName,
     'constant_value': ConstantValue,
     'default_value': DefaultValue,
@@ -389,6 +405,7 @@ class Generator(generator.Generator):
     'has_method_without_response': HasMethodWithoutResponse,
     'is_fixed_array_kind': mojom.IsFixedArrayKind,
     'is_handle': mojom.IsNonInterfaceHandleKind,
+    'is_map_kind': mojom.IsMapKind,
     'is_nullable_kind': mojom.IsNullableKind,
     'is_pointer_array_kind': IsPointerArrayKind,
     'is_struct_kind': mojom.IsStructKind,