gecko-dev/dom/xul/templates/nsTreeRows.h

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsTreeRows_h__
#define nsTreeRows_h__
#include "nsCOMPtr.h"
#include "nsTArray.h"
#include "pldhash.h"
#include "nsIXULTemplateResult.h"
#include "nsTemplateMatch.h"
#include "nsIRDFResource.h"
/**
* This class maintains the state of the XUL tree builder's
* rows. It maps a row number to the nsTemplateMatch object that
* populates the row.
*/
class nsTreeRows
{
public:
class iterator;
friend class iterator;
enum Direction { eDirection_Forwards = +1, eDirection_Backwards = -1 };
enum ContainerType {
eContainerType_Unknown = 0,
eContainerType_Noncontainer = 1,
eContainerType_Container = 2
};
enum ContainerState {
eContainerState_Unknown = 0,
eContainerState_Open = 1,
eContainerState_Closed = 2
};
enum ContainerFill {
eContainerFill_Unknown = 0,
eContainerFill_Empty = 1,
eContainerFill_Nonempty = 2
};
class Subtree;
/**
* A row in the tree. Contains the match that the row
* corresponds to, and a pointer to the row's subtree, if there
* are any.
*/
struct Row {
nsTemplateMatch* mMatch;
ContainerType mContainerType : 4;
ContainerState mContainerState : 4;
ContainerFill mContainerFill : 4;
Subtree* mSubtree; // XXX eventually move to hashtable
};
/**
* A subtree in the tree. A subtree contains rows, which may
* contain other subtrees.
*/
class Subtree {
protected:
friend class nsTreeRows; // so that it can access members, for now
/**
* The parent subtree; null if we're the root
*/
Subtree* mParent;
/**
* The number of immediate children in this subtree
*/
int32_t mCount;
/**
* The capacity of the subtree
*/
int32_t mCapacity;
/**
* The total number of rows in this subtree, recursively
* including child subtrees.
*/
int32_t mSubtreeSize;
/**
* The array of rows in the subtree
*/
Row* mRows;
public:
/**
* Creates a subtree with the specified parent.
*/
explicit Subtree(Subtree* aParent)
: mParent(aParent),
mCount(0),
mCapacity(0),
mSubtreeSize(0),
mRows(nullptr) {}
~Subtree();
/**
* Return the number of immediate child rows in the subtree
*/
int32_t Count() const { return mCount; }
/**
* Return the number of rows in this subtree, as well as all
* the subtrees it contains.
*/
int32_t GetSubtreeSize() const { return mSubtreeSize; }
/**
* Retrieve the immediate child row at the specified index.
*/
const Row& operator[](int32_t aIndex) const {
NS_PRECONDITION(aIndex >= 0 && aIndex < mCount, "bad index");
return mRows[aIndex]; }
/**
* Retrieve the immediate row at the specified index.
*/
Row& operator[](int32_t aIndex) {
NS_PRECONDITION(aIndex >= 0 && aIndex < mCount, "bad index");
return mRows[aIndex]; }
/**
* Remove all rows from the subtree.
*/
void Clear();
protected:
/**
* Insert an immediate child row at the specified index.
*/
iterator InsertRowAt(nsTemplateMatch* aMatch, int32_t aIndex);
/**
* Remove an immediate child row from the specified index.
*/
void RemoveRowAt(int32_t aChildIndex);
};
friend class Subtree;
protected:
/**
* A link in the path through the view's tree.
*/
struct Link {
Subtree* mParent;
int32_t mChildIndex;
Link&
operator=(const Link& aLink) {
mParent = aLink.mParent;
mChildIndex = aLink.mChildIndex;
return *this; }
bool
operator==(const Link& aLink) const {
return (mParent == aLink.mParent)
&& (mChildIndex == aLink.mChildIndex); }
Subtree* GetParent() { return mParent; }
const Subtree* GetParent() const { return mParent; }
int32_t GetChildIndex() const { return mChildIndex; }
Row& GetRow() { return (*mParent)[mChildIndex]; }
const Row& GetRow() const { return (*mParent)[mChildIndex]; }
};
public:
/**
* An iterator that can be used to traverse the tree view.
*/
class iterator {
protected:
int32_t mRowIndex;
nsAutoTArray<Link, 8> mLink;
void Next();
void Prev();
friend class Subtree; // so InsertRowAt can initialize us
friend class nsTreeRows; // so nsTreeRows can initialize us
/**
* Used by operator[]() to initialize an iterator.
*/
void Append(Subtree* aParent, int32_t aChildIndex);
/**
* Used by InsertRowAt() to initialize an iterator.
*/
void Push(Subtree *aParent, int32_t aChildIndex);
/**
* Used by operator[]() and InsertRowAt() to initialize an iterator.
*/
void SetRowIndex(int32_t aRowIndex) { mRowIndex = aRowIndex; }
/**
* Handy accessors to the top element.
*/
Link& GetTop() { return mLink[mLink.Length() - 1]; }
const Link& GetTop() const { return mLink[mLink.Length() - 1]; }
public:
iterator() : mRowIndex(-1) {}
iterator(const iterator& aIterator);
iterator& operator=(const iterator& aIterator);
bool operator==(const iterator& aIterator) const;
bool operator!=(const iterator& aIterator) const {
return !aIterator.operator==(*this); }
const Row& operator*() const { return GetTop().GetRow(); }
Row& operator*() { return GetTop().GetRow(); }
const Row* operator->() const { return &(GetTop().GetRow()); }
Row* operator->() { return &(GetTop().GetRow()); }
iterator& operator++() { Next(); return *this; }
iterator operator++(int) { iterator temp(*this); Next(); return temp; }
iterator& operator--() { Prev(); return *this; }
iterator operator--(int) { iterator temp(*this); Prev(); return temp; }
/**
* Return the current parent link
*/
Subtree* GetParent() { return GetTop().GetParent(); }
const Subtree* GetParent() const { return GetTop().GetParent(); }
/**
* Return the current child index
*/
int32_t GetChildIndex() const { return GetTop().GetChildIndex(); }
/**
* Return the depth of the path the iterator is maintaining
* into the tree.
*/
int32_t GetDepth() const { return mLink.Length(); }
/**
* Return the current row index of the iterator
*/
int32_t GetRowIndex() const { return mRowIndex; }
/**
* Pop the iterator up a level.
*/
iterator& Pop() { mLink.SetLength(GetDepth() - 1); return *this; }
};
/**
* Retrieve the first element in the view
*/
iterator First();
/**
* Retrieve (one past) the last element in the view
*/
iterator Last();
/**
* Find the row that contains the given resource
*/
iterator FindByResource(nsIRDFResource* aResource);
/**
* Find the row that contains the result
*/
iterator Find(nsIXULTemplateResult* aResult);
/**
* Retrieve the ith element in the view
*/
iterator operator[](int32_t aIndex);
nsTreeRows() : mRoot(nullptr) {}
~nsTreeRows() {}
/**
* Ensure that a child subtree exists within the specified parent
* at the specified child index within the parent. (In other
* words, create a subtree if one doesn't already exist.)
*/
Subtree*
EnsureSubtreeFor(Subtree* aParent, int32_t aChildIndex);
/**
* Ensure that a child subtree exists at the iterator's position.
*/
Subtree*
EnsureSubtreeFor(iterator& aIterator) {
return EnsureSubtreeFor(aIterator.GetParent(),
aIterator.GetChildIndex()); }
/**
* Get the child subtree for the specified parent at the specified
* child index. Optionally return the child subtree's size. Will
* return `null' if no subtree exists.
*/
Subtree*
GetSubtreeFor(const Subtree* aParent,
int32_t aChildIndex,
int32_t* aSubtreeSize = nullptr);
/**
* Retrieve the size of the subtree within the specified parent.
*/
int32_t
GetSubtreeSizeFor(const Subtree* aParent,
int32_t aChildIndex) {
int32_t size;
GetSubtreeFor(aParent, aChildIndex, &size);
return size; }
/**
* Retrieve the size of the subtree within the specified parent.
*/
int32_t
GetSubtreeSizeFor(const iterator& aIterator) {
int32_t size;
GetSubtreeFor(aIterator.GetParent(), aIterator.GetChildIndex(), &size);
return size; }
/**
* Remove the specified subtree for a row, leaving the row itself
* intact.
*/
void
RemoveSubtreeFor(Subtree* aParent, int32_t aChildIndex);
/**
* Remove the specified subtree for a row, leaving the row itself
* intact.
*/
void
RemoveSubtreeFor(iterator& aIterator) {
RemoveSubtreeFor(aIterator.GetParent(), aIterator.GetChildIndex()); }
/**
* Remove the specified row from the view
*/
int32_t
RemoveRowAt(iterator& aIterator) {
iterator temp = aIterator--;
Subtree* parent = temp.GetParent();
parent->RemoveRowAt(temp.GetChildIndex());
InvalidateCachedRow();
return parent->Count(); }
/**
* Insert a new match into the view
*/
iterator
InsertRowAt(nsTemplateMatch* aMatch, Subtree* aSubtree, int32_t aChildIndex) {
InvalidateCachedRow();
return aSubtree->InsertRowAt(aMatch, aChildIndex); }
/**
* Raw access to the rows; e.g., for sorting.
*/
Row*
GetRowsFor(Subtree* aSubtree) { return aSubtree->mRows; }
/**
* Remove all of the rows
*/
void Clear();
/**
* Return the total number of rows in the tree view.
*/
int32_t Count() const { return mRoot.GetSubtreeSize(); }
/**
* Retrieve the root subtree
*/
Subtree* GetRoot() { return &mRoot; }
/**
* Set the root resource for the view
*/
void SetRootResource(nsIRDFResource* aResource) {
mRootResource = aResource; }
/**
* Retrieve the root resource for the view
*/
nsIRDFResource* GetRootResource() {
return mRootResource.get(); }
/**
* Invalidate the cached row; e.g., because the view has changed
* in a way that would corrupt the iterator.
*/
void
InvalidateCachedRow() { mLastRow = iterator(); }
protected:
/**
* The root subtree.
*/
Subtree mRoot;
/**
* The root resource for the view
*/
nsCOMPtr<nsIRDFResource> mRootResource;
/**
* The last row that was asked for by operator[]. By remembering
* this, we can usually avoid the O(n) search through the row
* array to find the row at the specified index.
*/
iterator mLastRow;
};
#endif // nsTreeRows_h__