Adding block_begin and block_end to CodeWriter (#524)

* added block_begin and block_end util to CodeWriter.

* refactored convolution backprop to use block_begin() and block_end()

src/ngraph/codegen/code_writer.hpp

@@ -70,6 +70,18 @@ public:
 
     std::string generate_temporary_name(std::string prefix = "tempvar");
 
+    void block_begin()
+    {
+        *this << "{\n";
+        indent++;
+    }
+
+    void block_end()
+    {
+        indent--;
+        *this << "}\n";
+    }
+
 private:
     std::stringstream m_ss;
     bool m_pending_indent;

src/ngraph/runtime/cpu/cpu_emitter.cpp

@@ -2161,10 +2161,9 @@ namespace ngraph
                         writer << "memory::dims " << var << "{" << dims << "};\n";
                     };
 
-                    writer << "{\n";
-                    writer.indent++;
-                    writer << "try {\n";
-                    writer.indent++;
+                    writer.block_begin();
+                    writer << "try\n";
+                    writer.block_begin();
                     writer << "engine cpu_engine = engine(engine::cpu, 0);\n";
                     emit_memory_desc("data_desc", join(arg0_shape), elem_type, "nchw");
                     emit_memory_desc("delta_desc", join(arg1_shape), elem_type, "nchw");
@@ -2194,15 +2193,13 @@ namespace ngraph
                            "result);\n"
                            "stream s = stream(stream::kind::eager);\n"
                            "s.submit({bwd_weights}).wait();\n";
-                    writer.indent--;
-                    writer << "} catch (const mkldnn::error& e) {\n";
-                    writer.indent++;
+                    writer.block_end();
+                    writer << "catch (const mkldnn::error& e)\n";
+                    writer.block_begin();
                     writer << "throw ngraph::ngraph_error(\"MKLDNN ERROR (\" + std::to_string("
                               "e.status) + \"): \" + e.message);\n";
-                    writer.indent--;
-                    writer << "}\n";
-                    writer.indent--;
-                    writer << "}\n";
+                    writer.block_end();
+                    writer.block_end();
                 }
                 else
                 {
@@ -2275,10 +2272,9 @@ namespace ngraph
                         writer << "memory::dims " << var << "{" << dims << "};\n";
                     };
 
-                    writer << "{\n";
-                    writer.indent++;
-                    writer << "try {\n";
-                    writer.indent++;
+                    writer.block_begin();
+                    writer << "try\n";
+                    writer.block_begin();
                     writer << "engine cpu_engine = engine(engine::cpu, 0);\n";
                     emit_memory_desc("weight_desc", join(arg0_shape), elem_type, "oihw");
                     emit_memory_desc("delta_desc", join(arg1_shape), elem_type, "nchw");
@@ -2307,15 +2303,13 @@ namespace ngraph
                            "result);\n"
                            "stream s = stream(stream::kind::eager);\n"
                            "s.submit({bwd_data}).wait();\n";
-                    writer.indent--;
-                    writer << "} catch (const mkldnn::error& e) {\n";
-                    writer.indent++;
+                    writer.block_end();
+                    writer << "catch (const mkldnn::error& e)\n";
+                    writer.block_begin();
                     writer << "throw ngraph::ngraph_error(\"MKLDNN ERROR (\" + std::to_string("
                               "e.status) + \"): \" + e.message);\n";
-                    writer.indent--;
-                    writer << "}\n";
-                    writer.indent--;
-                    writer << "}\n";
+                    writer.block_end();
+                    writer.block_end();
                 }
                 else
                 {