restore mistakenly removed iffs in their explicit form

Due to confusion arisen from "iff" standing for "if and only if",
this commit uses the latter.

googlemock/include/gmock/gmock-spec-builders.h

@@ -332,7 +332,7 @@ class OnCallSpec : public UntypedOnCallSpecBase {
     return *this;
   }
 
-  // Returns true if the given arguments match the matchers.
+  // Returns true if and only if the given arguments match the matchers.
   bool Matches(const ArgumentTuple& args) const {
     return TupleMatches(matchers_, args) && extra_matcher_.Matches(args);
   }
@@ -390,7 +390,7 @@ class GTEST_API_ Mock {
       GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
 
   // Verifies all expectations on the given mock object and clears its
-  // default actions and expectations.  Returns true if the
+  // default actions and expectations.  Returns true if and only if the
   // verification was successful.
   static bool VerifyAndClear(void* mock_obj)
       GTEST_LOCK_EXCLUDED_(internal::g_gmock_mutex);
@@ -516,7 +516,8 @@ class GTEST_API_ Expectation {
   // The compiler-generated copy ctor and operator= work exactly as
   // intended, so we don't need to define our own.
 
-  // Returns true if rhs references the same expectation as this object does.
+  // Returns true if and only if rhs references the same expectation as this
+  // object does.
   bool operator==(const Expectation& rhs) const {
     return expectation_base_ == rhs.expectation_base_;
   }
@@ -598,8 +599,8 @@ class ExpectationSet {
   // The compiler-generator ctor and operator= works exactly as
   // intended, so we don't need to define our own.
 
-  // Returns true if rhs contains the same set of Expectation objects
-  // as this does.
+  // Returns true if and only if rhs contains the same set of Expectation
+  // objects as this does.
   bool operator==(const ExpectationSet& rhs) const {
     return expectations_ == rhs.expectations_;
   }
@@ -760,8 +761,8 @@ class GTEST_API_ ExpectationBase {
   // by the subclasses to implement the .Times() clause.
   void SpecifyCardinality(const Cardinality& cardinality);
 
-  // Returns true if the user specified the cardinality explicitly
-  // using a .Times().
+  // Returns true if and only if the user specified the cardinality
+  // explicitly using a .Times().
   bool cardinality_specified() const { return cardinality_specified_; }
 
   // Sets the cardinality of this expectation spec.
@@ -777,7 +778,7 @@ class GTEST_API_ ExpectationBase {
   void RetireAllPreRequisites()
       GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex);
 
-  // Returns true if this expectation is retired.
+  // Returns true if and only if this expectation is retired.
   bool is_retired() const
       GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
     g_gmock_mutex.AssertHeld();
@@ -791,28 +792,29 @@ class GTEST_API_ ExpectationBase {
     retired_ = true;
   }
 
-  // Returns true if this expectation is satisfied.
+  // Returns true if and only if this expectation is satisfied.
   bool IsSatisfied() const
       GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
     g_gmock_mutex.AssertHeld();
     return cardinality().IsSatisfiedByCallCount(call_count_);
   }
 
-  // Returns true if this expectation is saturated.
+  // Returns true if and only if this expectation is saturated.
   bool IsSaturated() const
       GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
     g_gmock_mutex.AssertHeld();
     return cardinality().IsSaturatedByCallCount(call_count_);
   }
 
-  // Returns true if this expectation is over-saturated.
+  // Returns true if and only if this expectation is over-saturated.
   bool IsOverSaturated() const
       GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
     g_gmock_mutex.AssertHeld();
     return cardinality().IsOverSaturatedByCallCount(call_count_);
   }
 
-  // Returns true if all pre-requisites of this expectation are satisfied.
+  // Returns true if and only if all pre-requisites of this expectation are
+  // satisfied.
   bool AllPrerequisitesAreSatisfied() const
       GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex);
 
@@ -855,7 +857,7 @@ class GTEST_API_ ExpectationBase {
   const char* file_;          // The file that contains the expectation.
   int line_;                  // The line number of the expectation.
   const std::string source_text_;  // The EXPECT_CALL(...) source text.
-  // True if the cardinality is specified explicitly.
+  // True if and only if the cardinality is specified explicitly.
   bool cardinality_specified_;
   Cardinality cardinality_;            // The cardinality of the expectation.
   // The immediate pre-requisites (i.e. expectations that must be
@@ -869,7 +871,7 @@ class GTEST_API_ ExpectationBase {
   // This group of fields are the current state of the expectation,
   // and can change as the mock function is called.
   int call_count_;  // How many times this expectation has been invoked.
-  bool retired_;    // True if this expectation has retired.
+  bool retired_;    // True if and only if this expectation has retired.
   UntypedActions untyped_actions_;
   bool extra_matcher_specified_;
   bool repeated_action_specified_;  // True if a WillRepeatedly() was specified.
@@ -1087,14 +1089,15 @@ class TypedExpectation : public ExpectationBase {
   // statement finishes and when the current thread holds
   // g_gmock_mutex.
 
-  // Returns true if this expectation matches the given arguments.
+  // Returns true if and only if this expectation matches the given arguments.
   bool Matches(const ArgumentTuple& args) const
       GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
     g_gmock_mutex.AssertHeld();
     return TupleMatches(matchers_, args) && extra_matcher_.Matches(args);
   }
 
-  // Returns true if this expectation should handle the given arguments.
+  // Returns true if and only if this expectation should handle the given
+  // arguments.
   bool ShouldHandleArguments(const ArgumentTuple& args) const
       GTEST_EXCLUSIVE_LOCK_REQUIRED_(g_gmock_mutex) {
     g_gmock_mutex.AssertHeld();