Rewrite FormatParagraph to handle newlines within input strings correctly

src/test/util_tests.cpp

@@ -404,7 +404,22 @@ BOOST_AUTO_TEST_CASE(test_FormatParagraph)
     BOOST_CHECK_EQUAL(FormatParagraph("test test", 4, 0), "test\ntest");
     BOOST_CHECK_EQUAL(FormatParagraph("testerde test", 4, 0), "testerde\ntest");
     BOOST_CHECK_EQUAL(FormatParagraph("test test", 4, 4), "test\n    test");
-    BOOST_CHECK_EQUAL(FormatParagraph("This is a very long test string. This is a second sentence in the very long test string."), "This is a very long test string. This is a second sentence in the very long\ntest string.");
+
+    // Make sure we don't indent a fully-new line following a too-long line ending
+    BOOST_CHECK_EQUAL(FormatParagraph("test test\nabc", 4, 4), "test\n    test\nabc");
+
+    BOOST_CHECK_EQUAL(FormatParagraph("This_is_a_very_long_test_string_without_any_spaces_so_it_should_just_get_returned_as_is_despite_the_length until it gets here", 79), "This_is_a_very_long_test_string_without_any_spaces_so_it_should_just_get_returned_as_is_despite_the_length\nuntil it gets here");
+
+    // Test wrap length is exact
+    BOOST_CHECK_EQUAL(FormatParagraph("a b c d e f g h i j k l m n o p q r s t u v w x y z 1 2 3 4 5 6 7 8 9 a b c de f g h i j k l m n o p", 79), "a b c d e f g h i j k l m n o p q r s t u v w x y z 1 2 3 4 5 6 7 8 9 a b c de\nf g h i j k l m n o p");
+    BOOST_CHECK_EQUAL(FormatParagraph("x\na b c d e f g h i j k l m n o p q r s t u v w x y z 1 2 3 4 5 6 7 8 9 a b c de f g h i j k l m n o p", 79), "x\na b c d e f g h i j k l m n o p q r s t u v w x y z 1 2 3 4 5 6 7 8 9 a b c de\nf g h i j k l m n o p");
+    // Indent should be included in length of lines
+    BOOST_CHECK_EQUAL(FormatParagraph("x\na b c d e f g h i j k l m n o p q r s t u v w x y z 1 2 3 4 5 6 7 8 9 a b c de f g h i j k l m n o p q r s t u v w x y z 0 1 2 3 4 5 6 7 8 9 a b c d e fg h i j k", 79, 4), "x\na b c d e f g h i j k l m n o p q r s t u v w x y z 1 2 3 4 5 6 7 8 9 a b c de\n    f g h i j k l m n o p q r s t u v w x y z 0 1 2 3 4 5 6 7 8 9 a b c d e fg\n    h i j k");
+
+    BOOST_CHECK_EQUAL(FormatParagraph("This is a very long test string. This is a second sentence in the very long test string.", 79), "This is a very long test string. This is a second sentence in the very long\ntest string.");
+    BOOST_CHECK_EQUAL(FormatParagraph("This is a very long test string.\nThis is a second sentence in the very long test string. This is a third sentence in the very long test string.", 79), "This is a very long test string.\nThis is a second sentence in the very long test string. This is a third\nsentence in the very long test string.");
+    BOOST_CHECK_EQUAL(FormatParagraph("This is a very long test string.\n\nThis is a second sentence in the very long test string. This is a third sentence in the very long test string.", 79), "This is a very long test string.\n\nThis is a second sentence in the very long test string. This is a third\nsentence in the very long test string.");
+    BOOST_CHECK_EQUAL(FormatParagraph("Testing that normal newlines do not get indented.\nLike here.", 79), "Testing that normal newlines do not get indented.\nLike here.");
 }
 
 BOOST_AUTO_TEST_CASE(test_FormatSubVersion)

src/utilstrencodings.cpp

@@ -478,34 +478,40 @@ bool ParseDouble(const std::string& str, double *out)
 std::string FormatParagraph(const std::string& in, size_t width, size_t indent)
 {
     std::stringstream out;
-    size_t col = 0;
     size_t ptr = 0;
+    size_t indented = 0;
     while (ptr < in.size())
     {
-        // Find beginning of next word
-        ptr = in.find_first_not_of(' ', ptr);
-        if (ptr == std::string::npos)
-            break;
-        // Find end of next word
-        size_t endword = in.find_first_of(' ', ptr);
-        if (endword == std::string::npos)
-            endword = in.size();
-        // Add newline and indentation if this wraps over the allowed width
-        if (col > 0)
-        {
-            if ((col + endword - ptr) > width)
-            {
-                out << '\n';
-                for(size_t i=0; i<indent; ++i)
-                    out << ' ';
-                col = 0;
-            } else
-                out << ' ';
-        }
-        // Append word
-        out << in.substr(ptr, endword - ptr);
-        col += endword - ptr + 1;
-        ptr = endword;
+        size_t lineend = in.find_first_of('\n', ptr);
+        if (lineend == std::string::npos) {
+            lineend = in.size();
+        }
+        const size_t linelen = lineend - ptr;
+        const size_t rem_width = width - indented;
+        if (linelen <= rem_width) {
+            out << in.substr(ptr, linelen + 1);
+            ptr = lineend + 1;
+            indented = 0;
+        } else {
+            size_t finalspace = in.find_last_of(" \n", ptr + rem_width);
+            if (finalspace == std::string::npos || finalspace < ptr) {
+                // No place to break; just include the entire word and move on
+                finalspace = in.find_first_of("\n ", ptr);
+                if (finalspace == std::string::npos) {
+                    // End of the string, just add it and break
+                    out << in.substr(ptr);
+                    break;
+                }
+            }
+            out << in.substr(ptr, finalspace - ptr) << "\n";
+            if (in[finalspace] == '\n') {
+                indented = 0;
+            } else if (indent) {
+                out << std::string(indent, ' ');
+                indented = indent;
+            }
+            ptr = finalspace + 1;
+        }
     }
     return out.str();
 }