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Merge pull request 'Implement Rope.rebalance & optimize pasting' (#18…
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…0) from rope-rebalance into main

Reviewed-on: https://git.samerion.com/Samerion/Fluid/pulls/180
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@ArthaTi
ArthaTi authored and Gitea committed Sep 9, 2024
2 parents b965e44 + 2cfc54b commit 28ca3ba
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Showing 3 changed files with 125 additions and 43 deletions.
10 changes: 5 additions & 5 deletions source/fluid/code_input.d
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1481,12 +1481,12 @@ class CodeInput : TextInput {
.walkLength;

return a.drop(min(commonIndent, localIndent));
});
})
.map!(a => Rope(a))
.array;

// Push each line
// TODO perhaps reformatting could be done during the same step
foreach (line; outdentedClipboard)
push(line);
// Push the clipboard
push(Rope.merge(outdentedClipboard));

reparse();

Expand Down
157 changes: 119 additions & 38 deletions source/fluid/rope.d
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,12 +30,15 @@ struct Rope {
/// Start and length of the rope, in UTF-8 bytes.
size_t start, length;

/// Depth of the node.
int depth = 1;

/// Create a rope holding given text.
this(inout const(char)[] text) inout pure nothrow {

// No text, stay with Rope.init
if (text == "")
this(null, 0, 0);
this(null, 0, 0, 1);
else
this(new inout RopeNode(text));

Expand All @@ -51,7 +54,7 @@ struct Rope {

// Both empty, return .init
if (right.length == 0)
this(null, 0, 0);
this(null, 0, 0, 1);

// Right node only, clone it
else
Expand All @@ -64,7 +67,7 @@ struct Rope {
this(left);

// Neither is empty, create a new node
else
else
this(new inout RopeNode(left, right));

}
Expand Down Expand Up @@ -107,21 +110,25 @@ struct Rope {
this.node = node;
this.start = 0;
this.length = node.length;
this.depth = node.isLeaf
? 1
: max(node.left.depth, node.right.depth) + 1;

}

/// Copy a `Rope`.
this(inout const Rope rope) inout pure nothrow {

this(rope.node, rope.start, rope.length);
this(rope.node, rope.start, rope.length, rope.depth);

}

private this(inout(RopeNode)* node, size_t start, size_t length) inout pure nothrow {
private this(inout(RopeNode)* node, size_t start, size_t length, int depth) inout pure nothrow {

this.node = node;
this.start = start;
this.length = length;
this.depth = depth;

}

Expand Down Expand Up @@ -209,26 +216,26 @@ struct Rope {
/// Concatenate two ropes together.
Rope opBinary(string op : "~")(const Rope that) const nothrow {

return Rope(this, that);
return Rope(this, that).rebalance();

}

/// Concatenate with a string.
Rope opBinary(string op : "~")(const(char)[] text) const nothrow {

return Rope(this, Rope(text));
return Rope(this, Rope(text)).rebalance();

}

/// ditto
Rope opBinaryRight(string op : "~")(const(char)[] text) const nothrow {

return Rope(Rope(text), this);
return Rope(Rope(text), this).rebalance();

}

/// True if the node is a leaf.
bool isLeaf() const nothrow {
bool isLeaf() const nothrow pure {

return node is null
|| node.isLeaf;
Expand Down Expand Up @@ -338,7 +345,7 @@ struct Rope {
}

/// Slice the rope.
Rope opIndex(size_t[2] slice, string caller = __PRETTY_FUNCTION__) const nothrow {
Rope opIndex(size_t[2] slice) const nothrow {

assert(slice[0] <= length,
format!"Left boundary of slice [%s .. %s] exceeds rope length %s"(slice[0], slice[1], length)
Expand Down Expand Up @@ -372,7 +379,7 @@ struct Rope {
}

// Overlap or a leaf: return both as they are
return Rope(node, slice[0], slice[1] - slice[0]);
return Rope(node, slice[0], slice[1] - slice[0], depth);

}

Expand Down Expand Up @@ -408,16 +415,58 @@ struct Rope {

}

/// Get the depth of the rope.
size_t depth() const nothrow {
/// Returns:
/// True if the rope is fairly balanced.
/// Params:
/// maxDistance = Maximum allowed `depth` difference
bool isBalanced(int maxDistance = 3) const nothrow {

// Leaves are always balanced
if (isLeaf) return true;

const depthDifference = node.left.depth - node.right.depth;

return depthDifference >= -maxDistance
&& depthDifference <= +maxDistance;

}

/// Returns:
/// If the rope is unbalanced, returns a copy of the rope, optimized to improve reading performance.
/// If the rope is already balanced, returns the original rope unmodified.
/// Params:
/// maxDistance = Maximum allowed `depth` difference before rebalancing happens.
Rope rebalance() const nothrow
out (r) {
assert(r.isBalanced,
format("rebalance(%s) failed. Depth %s (left %s, right %s)", this, depth, left.depth, right.depth)
.assumeWontThrow);
}
do {

import std.array;

if (isBalanced) return this;

// Leafs have depth of 1
if (isLeaf) return 1;
return merge(byNode.array);

return max(node.left.depth, node.right.depth) + 1;
}

/// Returns: A rope created by concatenating an array of leaves together.
static Rope merge(Rope[] leaves) nothrow {

if (leaves.length == 0)
return Rope.init;
else if (leaves.length == 1)
return leaves[0];
else if (leaves.length == 2)
return Rope(leaves[0], leaves[1]);
else
return Rope(merge(leaves[0 .. $/2]), merge(leaves[$/2 .. $]));

}


unittest {

auto a = Rope();
Expand Down Expand Up @@ -507,9 +556,9 @@ struct Rope {
assert(ab[3..$].left.equal(""));
assert(ab[4..$].left.equal(""));
assert(ab[0..4].left.equal("ABC"));
assert(Rope(ab.node, 0, 3).left.equal("ABC"));
assert(Rope(ab.node, 0, 2).left.equal("AB"));
assert(Rope(ab.node, 0, 1).left.equal("A"));
assert(Rope(ab.node, 0, 3, 1).left.equal("ABC"));
assert(Rope(ab.node, 0, 2, 1).left.equal("AB"));
assert(Rope(ab.node, 0, 1, 1).left.equal("A"));
assert(ab[0..0].left.equal(""));
assert(ab[1..1].left.equal(""));
assert(ab[4..4].left.equal(""));
Expand All @@ -532,8 +581,8 @@ struct Rope {
assert(ab[4..$].left.equal(""));
assert(ab[0..4].left.equal("BC"));
assert(ab[0..3].left.equal("BC"));
assert(Rope(ab.node, 0, 2).left.equal("BC"));
assert(Rope(ab.node, 0, 1).left.equal("B"));
assert(Rope(ab.node, 0, 2, 1).left.equal("BC"));
assert(Rope(ab.node, 0, 1, 1).left.equal("B"));
assert(ab[0..0].left.equal(""));
assert(ab[1..1].left.equal(""));
assert(ab[4..4].left.equal(""));
Expand Down Expand Up @@ -566,10 +615,10 @@ struct Rope {

assert(ab.right.equal("DEF"));
assert(ab[1..$].right.equal("DEF"));
assert(Rope(ab.node, 3, 3).right.equal("DEF"));
assert(Rope(ab.node, 4, 2).right.equal("EF"));
assert(Rope(ab.node, 4, 1).right.equal("E"));
assert(Rope(ab.node, 3, 2).right.equal("DE"));
assert(Rope(ab.node, 3, 3, 1).right.equal("DEF"));
assert(Rope(ab.node, 4, 2, 1).right.equal("EF"));
assert(Rope(ab.node, 4, 1, 1).right.equal("E"));
assert(Rope(ab.node, 3, 2, 1).right.equal("DE"));
assert(ab[2..$-1].right.equal("DE"));
assert(ab[1..1].right.equal(""));
assert(ab[4..4].right.equal(""));
Expand All @@ -589,11 +638,11 @@ struct Rope {

assert(ab.right.equal("EF"));
assert(ab[1..$].right.equal("EF"));
assert(Rope(ab.node, 3, 1).right.equal("F"));
assert(Rope(ab.node, 4, 0).right.equal(""));
assert(Rope(ab.node, 1, 2).right.equal("E"));
assert(Rope(ab.node, 2, 1).right.equal("E"));
assert(Rope(ab.node, 3, 0).right.equal(""));
assert(Rope(ab.node, 3, 1, 1).right.equal("F"));
assert(Rope(ab.node, 4, 0, 1).right.equal(""));
assert(Rope(ab.node, 1, 2, 1).right.equal("E"));
assert(Rope(ab.node, 2, 1, 1).right.equal("E"));
assert(Rope(ab.node, 3, 0, 1).right.equal(""));
assert(ab[1..1].right.equal(""));
assert(ab[4..4].right.equal(""));

Expand Down Expand Up @@ -764,7 +813,7 @@ struct Rope {
auto split = split(index);

// Insert the element
return Rope(split.left, Rope(value, split.right));
return Rope(split.left, Rope(value, split.right)).rebalance();

}

Expand Down Expand Up @@ -831,7 +880,7 @@ struct Rope {
value,
rightSplit.right,
),
);
).rebalance();

}

Expand Down Expand Up @@ -959,7 +1008,7 @@ struct Rope {

auto left = this;

return this = Rope(left, Rope(value));
return this = Rope(left, Rope(value)).rebalance;

}

Expand All @@ -968,7 +1017,7 @@ struct Rope {

auto left = this;

return this = Rope(left, value);
return this = Rope(left, value).rebalance();

}

Expand All @@ -988,7 +1037,7 @@ struct Rope {

}

/// Perform deep-first search through nodes of the rope.
/// Perform deep-first search through leaf nodes of the rope.
auto byNode() inout {

import std.container.dlist;
Expand Down Expand Up @@ -1220,6 +1269,10 @@ struct Rope {
/// The return value includes a `start` field which indicates the exact index the resulting range starts with.
DiffRegion diff(const Rope other) const {

if (this is other) {
return DiffRegion.init;
}

if (!isLeaf) {

// Left side is identical, compare right side only
Expand All @@ -1240,10 +1293,10 @@ struct Rope {

}

Rope result;

// Perform string comparison
const prefix = commonPrefix(this[], other[]).length;
const prefix = commonPrefix(
BasicRopeRange(this[]),
BasicRopeRange(other[])).length;
const suffix = commonPrefix(this[prefix..$].retro, other[prefix..$].retro).length;

const start = prefix;
Expand Down Expand Up @@ -1560,3 +1613,31 @@ unittest {

/// `std.utf.codeLength` implementation for Rope.
alias codeLength(T : Rope) = imported!"std.utf".codeLength!char;

/// A wrapper over Range which disables slicing. Some algorithms assume slicing is faster than regular range access,
/// but it's not the case for `Rope`.
struct BasicRopeRange {

Rope rope;

size_t length() const {
return rope.length;
}

bool empty() const {
return rope.empty;
}

void popFront() {
rope.popFront;
}

char front() const {
return rope.front;
}

BasicRopeRange save() {
return this;
}

}
1 change: 1 addition & 0 deletions source/fluid/text_input.d
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1366,6 +1366,7 @@ class TextInput : InputNode!Node, FluidScrollable {

// Insert the text by replacing the old node, if present
value = value.replace(caretIndex - originalLength, caretIndex, Rope(bufferNode));
assert(value.isBalanced);

// Move the caret
caretIndex = caretIndex + ch.length;
Expand Down

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