LibMarkdown: Drop MD prefixes and move into "Markdown" namespace :^)

1 files changed, 235 insertions, 0 deletions

diff --git a/Libraries/LibMarkdown/Text.cpp b/Libraries/LibMarkdown/Text.cpp
new file mode 100644
index 0000000000..6bfe89d69c
--- /dev/null
+++ b/Libraries/LibMarkdown/Text.cpp
@@ -0,0 +1,235 @@
+/*
+ * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/StringBuilder.h>
+#include <LibMarkdown/Text.h>
+#include <string.h>
+
+namespace Markdown {
+
+static String unescape(const StringView& text)
+{
+    StringBuilder builder;
+    for (size_t i = 0; i < text.length(); ++i) {
+        if (text[i] == '\\' && i != text.length() - 1) {
+            builder.append(text[i + 1]);
+            i++;
+            continue;
+        }
+        builder.append(text[i]);
+    }
+    return builder.build();
+}
+
+String Text::render_to_html() const
+{
+    StringBuilder builder;
+
+    Vector<String> open_tags;
+    Style current_style;
+
+    for (auto& span : m_spans) {
+        struct TagAndFlag {
+            String tag;
+            bool Style::*flag;
+        };
+        TagAndFlag tags_and_flags[] = {
+            { "i", &Style::emph },
+            { "b", &Style::strong },
+            { "code", &Style::code }
+        };
+        auto it = open_tags.find([&](const String& open_tag) {
+            if (open_tag == "a" && current_style.href != span.style.href)
+                return true;
+            for (auto& tag_and_flag : tags_and_flags) {
+                if (open_tag == tag_and_flag.tag && !(span.style.*tag_and_flag.flag))
+                    return true;
+            }
+            return false;
+        });
+
+        if (!it.is_end()) {
+            // We found an open tag that should
+            // not be open for the new span. Close
+            // it and all the open tags that follow
+            // it.
+            for (ssize_t j = open_tags.size() - 1; j >= static_cast<ssize_t>(it.index()); --j) {
+                auto& tag = open_tags[j];
+                builder.appendf("</%s>", tag.characters());
+                if (tag == "a") {
+                    current_style.href = {};
+                    continue;
+                }
+                for (auto& tag_and_flag : tags_and_flags)
+                    if (tag == tag_and_flag.tag)
+                        current_style.*tag_and_flag.flag = false;
+            }
+            open_tags.shrink(it.index());
+        }
+        if (current_style.href.is_null() && !span.style.href.is_null()) {
+            open_tags.append("a");
+            builder.appendf("<a href=\"%s\">", span.style.href.characters());
+        }
+        for (auto& tag_and_flag : tags_and_flags) {
+            if (current_style.*tag_and_flag.flag != span.style.*tag_and_flag.flag) {
+                open_tags.append(tag_and_flag.tag);
+                builder.appendf("<%s>", tag_and_flag.tag.characters());
+            }
+        }
+
+        current_style = span.style;
+        builder.append(span.text);
+    }
+
+    for (ssize_t i = open_tags.size() - 1; i >= 0; --i) {
+        auto& tag = open_tags[i];
+        builder.appendf("</%s>", tag.characters());
+    }
+
+    return builder.build();
+}
+
+String Text::render_for_terminal() const
+{
+    StringBuilder builder;
+
+    for (auto& span : m_spans) {
+        bool needs_styling = span.style.strong || span.style.emph || span.style.code;
+        if (needs_styling) {
+            builder.append("\033[");
+            bool first = true;
+            if (span.style.strong || span.style.code) {
+                builder.append('1');
+                first = false;
+            }
+            if (span.style.emph) {
+                if (!first)
+                    builder.append(';');
+                builder.append('4');
+            }
+            builder.append('m');
+        }
+
+        builder.append(span.text.characters());
+
+        if (needs_styling)
+            builder.append("\033[0m");
+
+        if (!span.style.href.is_null()) {
+            // When rendering for the terminal, ignore any
+            // non-absolute links, because the user has no
+            // chance to follow them anyway.
+            if (strstr(span.style.href.characters(), "://") != nullptr) {
+                builder.appendf(" <%s>", span.style.href.characters());
+            }
+        }
+    }
+
+    return builder.build();
+}
+
+bool Text::parse(const StringView& str)
+{
+    Style current_style;
+    size_t current_span_start = 0;
+    int first_span_in_the_current_link = -1;
+
+    auto append_span_if_needed = [&](size_t offset) {
+        if (current_span_start != offset) {
+            Span span {
+                unescape(str.substring_view(current_span_start, offset - current_span_start)),
+                current_style
+            };
+            m_spans.append(move(span));
+        }
+    };
+
+    for (size_t offset = 0; offset < str.length(); offset++) {
+        char ch = str[offset];
+
+        bool is_escape = ch == '\\';
+        if (is_escape && offset != str.length() - 1) {
+            offset++;
+            continue;
+        }
+
+        bool is_special_character = false;
+        is_special_character |= ch == '`';
+        if (!current_style.code)
+            is_special_character |= ch == '*' || ch == '_' || ch == '[' || ch == ']';
+        if (!is_special_character)
+            continue;
+
+        append_span_if_needed(offset);
+
+        switch (ch) {
+        case '`':
+            current_style.code = !current_style.code;
+            break;
+        case '*':
+        case '_':
+            if (offset + 1 < str.length() && str[offset + 1] == ch) {
+                offset++;
+                current_style.strong = !current_style.strong;
+            } else {
+                current_style.emph = !current_style.emph;
+            }
+            break;
+        case '[':
+            ASSERT(first_span_in_the_current_link == -1);
+            first_span_in_the_current_link = m_spans.size();
+            break;
+        case ']': {
+            ASSERT(first_span_in_the_current_link != -1);
+            ASSERT(offset + 2 < str.length());
+            offset++;
+            ASSERT(str[offset] == '(');
+            offset++;
+            size_t start_of_href = offset;
+
+            do
+                offset++;
+            while (offset < str.length() && str[offset] != ')');
+
+            const StringView href = str.substring_view(start_of_href, offset - start_of_href);
+            for (size_t i = first_span_in_the_current_link; i < m_spans.size(); i++)
+                m_spans[i].style.href = href;
+            first_span_in_the_current_link = -1;
+            break;
+        }
+        default:
+            ASSERT_NOT_REACHED();
+        }
+
+        current_span_start = offset + 1;
+    }
+
+    append_span_if_needed(str.length());
+
+    return true;
+}
+
+}