Re-factor elide code and test it.

4 files changed, 30 insertions, 13 deletions

diff --git a/src/build.cc b/src/build.cc
index 09d7f65..a1c94e4 100644
--- a/src/build.cc
+++ b/src/build.cc
@@ -236,28 +236,17 @@ void BuildStatus::PrintStatus(Edge* edge) {
   to_print = FormatProgressStatus(progress_status_format_) + to_print;
 
   if (smart_terminal_ && !force_full_command) {
-    const int kMargin = 3;  // Space for "...".
 #ifndef _WIN32
     // Limit output to width of the terminal if provided so we don't cause
     // line-wrapping.
     winsize size;
     if ((ioctl(0, TIOCGWINSZ, &size) == 0) && size.ws_col) {
-      if (to_print.size() + kMargin > size.ws_col) {
-        int elide_size = (size.ws_col - kMargin) / 2;
-        to_print = to_print.substr(0, elide_size)
-          + "..."
-          + to_print.substr(to_print.size() - elide_size, elide_size);
-      }
+      to_print = ElideMiddle(to_print, size.ws_col);
     }
 #else
     // Don't use the full width or console will move to next line.
     size_t width = static_cast<size_t>(csbi.dwSize.X) - 1;
-    if (to_print.size() + kMargin > width) {
-      int elide_size = (width - kMargin) / 2;
-      to_print = to_print.substr(0, elide_size)
-        + "..."
-        + to_print.substr(to_print.size() - elide_size, elide_size);
-    }
+    to_print = ElideMiddle(to_print, width);
 #endif
   }
 
diff --git a/src/util.cc b/src/util.cc
index ca05292..cb3e141 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -311,3 +311,16 @@ double GetLoadAverage()
   return GetLoadAverage_unix();
 #endif // _WIN32
 }
+
+string ElideMiddle(const string& str, size_t width)
+{
+  const int kMargin = 3;  // Space for "...".
+  string result = str;
+  if (result.size() + kMargin > width) {
+    int elide_size = (width - kMargin) / 2;
+    result = result.substr(0, elide_size)
+      + "..."
+      + result.substr(result.size() - elide_size, elide_size);
+  }
+  return result;
+}
diff --git a/src/util.h b/src/util.h
index fd91772..4c0f4bb 100644
--- a/src/util.h
+++ b/src/util.h
@@ -66,6 +66,10 @@ string StripAnsiEscapeCodes(const string& in);
 /// on error.
 double GetLoadAverage();
 
+/// Elide the given string @a str with '...' in the middle if the length
+/// exceeds @a width.
+string ElideMiddle(const string& str, size_t width);
+
 #ifdef _MSC_VER
 #define snprintf _snprintf
 #define fileno _fileno
diff --git a/src/util_test.cc b/src/util_test.cc
index 23d4b83..5ace5e7 100644
--- a/src/util_test.cc
+++ b/src/util_test.cc
@@ -136,3 +136,14 @@ TEST(StripAnsiEscapeCodes, StripColors) {
   EXPECT_EQ("affixmgr.cxx:286:15: warning: using the result... [-Wparentheses]",
             stripped);
 }
+
+TEST(ElideMiddle, NothingToElide) {
+  string input = "Nothing to elide in this short string.";
+  EXPECT_EQ(input, ElideMiddle(input, 80));
+}
+
+TEST(ElideMiddle, ElideInTheMiddle) {
+  string input = "01234567890123456789";
+  string elided = ElideMiddle(input, 10);
+  EXPECT_EQ("012...789", elided);
+}