為 LiteIDE 添加選中標記

(金慶的專欄 2018.1)

"[Eclipse Mark Occurrences](http://www.eclipse.org/pdt/help/html/mark_occurrences.htm)"
可以在滾動條旁邊顯示文中所有選中的標記，
可以選中某個變量顯示有多少引用。不過 GoClipse 沒有 "Mark Occurrences" 功能。
VS code 有此功能。

LiteIDE 對于build錯誤會顯示這種標記，所以感覺可以依此實現"Mark Occurrences"。

首先找到了打標記的功能。標記用到顏色，所以搜'QColor', 找到了：
```c++
QColor markTypeColor(LiteApi::EditorNaviagteType type)
```

相關的接口會用到：
```c++
    void insertNavigateMark(int line, LiteApi::EditorNaviagteType type, const QString &msg, const char* tag);
    void clearAllNavigateMark(LiteApi::EditorNaviagteType types, const char *tag);
```

尋找選中時觸發標記的代碼，選中或搜索時會有圓角框圈出，搜"find", 找到：
```c++
if (!m_findExpression.isEmpty()) {
    if (!findInBlock(block,m_findExpression,pos,m_findFlags,cur)) {
        break;
    }
    ...
    painter.drawRoundedRect(offsetX+left,r.top()+l.y(),right-left,l.height(),3,3);
} else if (!m_selectionExpression.isEmpty()) {
    if (!findInBlock(block,m_selectionExpression,pos,QTextDocument::FindWholeWords,cur)) {
        break;
    }
    ...
    painter.drawRoundedRect(offsetX+left,r.top()+l.y(),right-left,l.height(),3,3);
}
```

發現畫方框僅在可視區域。續繼查找 m_findExpression 和 m_selectionExpression 更改處，
添加 'updateNavigateMarks()'

```c++
void LiteEditorWidgetBase::setFindOption(LiteApi::FindOption *opt)
{
    ...
+   updateNavigateMarks(LiteApi::EditorNavigateFind);
    viewport()->update();
}
```

```c++
void LiteEditorWidgetBase::slotSelectionChanged()
{
    ...
        m_selectionExpression.setPattern(pattern);
+       updateNavigateMarks(LiteApi::EditorNavigateSelection);
        viewport()->update();
    ...
}
```

須添加2個新的類型：
```c++
enum EditorNaviagteType{
    EditorNavigateNormal = 1,
    EditorNavigateWarning = 2,
    EditorNavigateError = 4,
    EditorNavigateReload = 8,
+   EditorNavigateFind = 16,
+   EditorNavigateSelection = 32,
    EditorNavigateBad = EditorNavigateWarning|EditorNavigateError
};
```

搜索 `EditorNavigateWarning`, 找到因新增類型須更改優先級表和顏色函數。

```c++
const int PRIORITYLIST_LENGTH = 7;
const LiteApi::EditorNaviagteType MARKTYPE_PRIORITYLIST[PRIORITYLIST_LENGTH] = {
        ..., LiteApi::EditorNavigateFind, LiteApi::EditorNavigateSelection, ...
    };
...
inline QColor markTypeColor(LiteApi::EditorNaviagteType type) {
    switch(type) {
    ...
    case LiteApi::EditorNavigateNormal:
        return Qt::darkGreen;
    case LiteApi::EditorNavigateReload:
        return Qt::darkBlue;
    }
}
```

更新標記時先清空，然后逐行搜索添加標記：
```c++
// Update selections or find marks.
void LiteEditorWidgetBase::updateNavigateMarks(LiteApi::EditorNaviagteType type)
{
    clearAllNavigateMark(type, "");
    ...

    QTextDocument *doc = this->document();
    for (QTextBlock it = doc->begin(); it != doc->end(); it = it.next())
    {
        if (!needToMarkBlock(it, type))
            continue;
        int lineNumber = it.blockNumber() + 1;
        insertNavigateMark(lineNumber, type, QString("%1: %2").arg(lineNumber).arg(it.text()), "");
    }
}

bool LiteEditorWidgetBase::needToMarkBlock(
    const QTextBlock &block, LiteApi::EditorNaviagteType type) const
{
    ...
    if (LiteApi::EditorNavigateFind == type)
        return findInBlock(block, m_findExpression, pos, m_findFlags, cur);
    if (LiteApi::EditorNavigateSelection == type)
        return findInBlock(block, m_selectionExpression, pos,
                           QTextDocument::FindWholeWords, cur);
    return false;
}
```

已合并主干：
```
Revision: 43f4954b0b802eccbbf451136be600bfcec71f27
Author: Jin Qing <jinq0123@163.com>
Date: 18.1.5 19:08:26
Message:
Add "Mark Occurrences" function that marks selections and findings.

----
Modified: liteidex/src/api/liteeditorapi/liteeditorapi.h
Modified: liteidex/src/plugins/liteeditor/liteeditorwidgetbase.cpp
Modified: liteidex/src/plugins/liteeditor/liteeditorwidgetbase.h
```