Add json encode/decode for php. (#3226)

* Add json encode/decode for php.

* Fix php conformance test on 32-bit machines.

* Fix conformance test for c extension.

* Fix comments

1 files changed, 27 insertions, 5 deletions

diff --git a/php/src/Google/Protobuf/Internal/Descriptor.php b/php/src/Google/Protobuf/Internal/Descriptor.php
index f8d24e45..44225ad2 100644
--- a/php/src/Google/Protobuf/Internal/Descriptor.php
+++ b/php/src/Google/Protobuf/Internal/Descriptor.php
@@ -37,6 +37,8 @@ class Descriptor
 
     private $full_name;
     private $field = [];
+    private $json_to_field = [];
+    private $name_to_field = [];
     private $nested_type = [];
     private $enum_type = [];
     private $klass;
@@ -66,6 +68,8 @@ class Descriptor
     public function addField($field)
     {
         $this->field[$field->getNumber()] = $field;
+        $this->json_to_field[$field->getJsonName()] = $field;
+        $this->name_to_field[$field->getName()] = $field;
     }
 
     public function getField()
@@ -95,11 +99,29 @@ class Descriptor
 
     public function getFieldByNumber($number)
     {
-      if (!isset($this->field[$number])) {
-        return NULL;
-      } else {
-        return $this->field[$number];
-      }
+        if (!isset($this->field[$number])) {
+          return NULL;
+        } else {
+          return $this->field[$number];
+        }
+    }
+
+    public function getFieldByJsonName($json_name)
+    {
+        if (!isset($this->json_to_field[$json_name])) {
+          return NULL;
+        } else {
+          return $this->json_to_field[$json_name];
+        }
+    }
+
+    public function getFieldByName($name)
+    {
+        if (!isset($this->name_to_field[$name])) {
+          return NULL;
+        } else {
+          return $this->name_to_field[$name];
+        }
     }
 
     public function setClass($klass)