IMPALA-1477: implement UUID function

Utilize Boost UUID libraries to generate UUID values.
Usage: select uuid();

Change-Id: I932f78952d65f4073d8177c6e80693586e6285cb
Reviewed-on: http://gerrit.cloudera.org:8080/647
Reviewed-by: Alex Behm <alex.behm@cloudera.com>
Tested-by: Internal Jenkins

be/src/exprs/expr-test.cc

@@ -22,6 +22,7 @@
 #include <boost/date_time/posix_time/posix_time.hpp>
 #include <boost/lexical_cast.hpp>
 #include <boost/random/mersenne_twister.hpp>
+#include <boost/regex.hpp>
 #include <boost/unordered_map.hpp>
 #include <gtest/gtest.h>
 
@@ -305,6 +306,16 @@ class ExprTest : public testing::Test {
     EXPECT_EQ(expected_result, tmp) << expr;
   }
 
+  string TestStringValueRegex(const string& expr, const string& regex) {
+    StringValue* result;
+    GetValue(expr, TYPE_STRING, reinterpret_cast<void **>(&result));
+    static const boost::regex e(regex);
+    string result_cxxstr(result->ptr, result->len);
+    const bool is_regex_match = regex_match(result_cxxstr, e);
+    EXPECT_TRUE(is_regex_match);
+    return result_cxxstr;
+  }
+
   // We can't put this into TestValue() because GTest can't resolve
   // the ambiguity in TimestampValue::operator==, even with the appropriate casts.
   void TestTimestampValue(const string& expr, const TimestampValue& expected_result) {
@@ -5718,7 +5729,18 @@ TEST_F(ExprTest, BitByteBuiltins) {
   TestValue("shiftright(cast(1 as BIGINT), -2)", TYPE_BIGINT, 4);
   TestValue("rotateleft(4, -3)", TYPE_TINYINT, -128);
   TestValue("rotateright(256, -2)", TYPE_SMALLINT, 1024);
+}
 
+TEST_F(ExprTest, UuidTest) {
+  boost::unordered_set<string> string_set;
+  const unsigned int NUM_UUIDS = 10;
+  const string regex(
+      "[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}");
+  for (int i = 0; i < NUM_UUIDS; ++i) {
+    const string uuid_str = TestStringValueRegex("uuid()", regex);
+    string_set.insert(uuid_str);
+  }
+  EXPECT_TRUE(string_set.size() == NUM_UUIDS);
 }
 
 } // namespace impala

be/src/exprs/utility-functions.cc

@@ -15,6 +15,9 @@
 #include "exprs/utility-functions.h"
 
 #include <gutil/strings/substitute.h>
+#include <boost/uuid/uuid_generators.hpp>
+#include <boost/uuid/uuid.hpp>
+#include <boost/uuid/uuid_io.hpp>
 
 #include "exprs/anyval-util.h"
 #include "runtime/runtime-state.h"
@@ -111,6 +114,37 @@ StringVal UtilityFunctions::CurrentDatabase(FunctionContext* ctx) {
   return (database.len > 0) ? database : StringVal::null();
 }
 
+void UtilityFunctions::UuidPrepare(FunctionContext* ctx,
+    FunctionContext::FunctionStateScope scope) {
+  if (scope == FunctionContext::THREAD_LOCAL) {
+    if (ctx->GetFunctionState(FunctionContext::THREAD_LOCAL) == NULL) {
+      boost::uuids::random_generator* uuid_gen =
+        new boost::uuids::random_generator;
+      ctx->SetFunctionState(scope, uuid_gen);
+    }
+  }
+}
+
+StringVal UtilityFunctions::Uuid(FunctionContext* ctx) {
+  void* uuid_gen = ctx->GetFunctionState(FunctionContext::THREAD_LOCAL);
+  DCHECK(uuid_gen != NULL);
+  boost::uuids::uuid uuid_value =
+    (*reinterpret_cast<boost::uuids::random_generator*>(uuid_gen))();
+  const std::string cxx_string = boost::uuids::to_string(uuid_value);
+  return StringVal::CopyFrom(ctx,
+      reinterpret_cast<const uint8_t*>(cxx_string.c_str()),
+      cxx_string.length());
+}
+
+void UtilityFunctions::UuidClose(FunctionContext* ctx,
+    FunctionContext::FunctionStateScope scope){
+  if (scope == FunctionContext::THREAD_LOCAL) {
+    void* uuid_gen = ctx->GetFunctionState(FunctionContext::THREAD_LOCAL);
+    DCHECK(uuid_gen != NULL);
+    delete uuid_gen;
+  }
+}
+
 template<typename T>
 StringVal UtilityFunctions::TypeOf(FunctionContext* ctx, const T& /*input_val*/) {
   FunctionContext::TypeDesc type_desc = *(ctx->GetArgType(0));

be/src/exprs/utility-functions.h

@@ -58,6 +58,13 @@ class UtilityFunctions {
   /// database from the parent session of this query.
   static StringVal CurrentDatabase(FunctionContext* ctx);
 
+  /// Implementation of the Uuid() function.
+  static StringVal Uuid(FunctionContext* ctx);
+  static void UuidPrepare(FunctionContext* ctx,
+      FunctionContext::FunctionStateScope scope);
+  static void UuidClose(FunctionContext* ctx,
+      FunctionContext::FunctionStateScope scope);
+
   /// Implementation of the typeOf() function. Returns the type of the input
   /// expression. input_val is not used and it is kept here in order to let
   /// the compiler generate the corresponding fully-qualified function name.

common/function-registry/impala_functions.py

@@ -535,6 +535,10 @@ def symbol(class_name, fn_name, templated_type = None):
   [['isnotfalse'], 'BOOLEAN', ['BOOLEAN'], 'impala::ConditionalFunctions::IsNotFalse'],
 
   # Utility functions
+  [['uuid'], 'STRING', [],
+   '_ZN6impala16UtilityFunctions4UuidEPN10impala_udf15FunctionContextE',
+   '_ZN6impala16UtilityFunctions11UuidPrepareEPN10impala_udf15FunctionContextENS2_18FunctionStateScopeE',
+   '_ZN6impala16UtilityFunctions9UuidCloseEPN10impala_udf15FunctionContextENS2_18FunctionStateScopeE'],
   [['current_database'], 'STRING', [], 'impala::UtilityFunctions::CurrentDatabase'],
   [['user'], 'STRING', [], 'impala::UtilityFunctions::User'],
   [['effective_user'], 'STRING', [], 'impala::UtilityFunctions::EffectiveUser'],