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Feature/connection refactor #88

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merged 2 commits into from
Feb 25, 2016
Merged

Feature/connection refactor #88

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aeb6129
minor refactor of connection code, plus fix for #87
rachel-fenichel Feb 25, 2016
25c0eb7
Clean up comment
rachel-fenichel Feb 25, 2016
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132 changes: 107 additions & 25 deletions core/connection.js
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Original file line number Diff line number Diff line change
Expand Up @@ -68,6 +68,17 @@ Blockly.Connection.STRING = 2;
*/
Blockly.Connection.NUMBER = 3;

/**
* Constants for checking whether two connections are compatible.
*/
Blockly.Connection.CAN_CONNECT = 0;
Blockly.Connection.REASON_SELF_CONNECTION = 1;
Blockly.Connection.REASON_WRONG_TYPE = 2;
Blockly.Connection.REASON_MUST_DISCONNECT = 3;
Blockly.Connection.REASON_TARGET_NULL = 4;
Blockly.Connection.REASON_CHECKS_FAILED = 5;
Blockly.Connection.REASON_DIFFERENT_WORKSPACES = 6;

/**
* Connection this connection connects to. Null if not connected.
* @type {Blockly.Connection}
Expand Down Expand Up @@ -160,26 +171,71 @@ Blockly.Connection.prototype.isSuperior = function() {
this.type == Blockly.NEXT_STATEMENT;
};

/**
* Checks whether the current connection can connect with the target
* connection.
* @param (Blockly.Connection) target Connection to check compatibility with.
* @return {int} Blockly.Connection.CAN_CONNECT if the connection is legal,
* an error code otherwise.
* @private
*/
Blockly.Connection.prototype.canConnectWithReason_ = function(target) {
if (!target) {
return Blockly.Connection.REASON_TARGET_NULL;
} else if (this.sourceBlock_ && target.sourceBlock_ == this.sourceBlock_) {
return Blockly.Connection.REASON_SELF_CONNECTION;
} else if (target.type != Blockly.OPPOSITE_TYPE[this.type]) {
return Blockly.Connection.REASON_WRONG_TYPE;
} else if (this.targetConnection) {
return Blockly.Connection.REASON_MUST_DISCONNECT;
} else if (this.sourceBlock_ && target.sourceBlock_ &&
this.sourceBlock_.workspace !== target.sourceBlock_.workspace) {
return Blockly.Connection.REASON_DIFFERENT_WORKSPACES;
} else if (!this.checkType_(target)) {
return Blockly.Connection.REASON_CHECKS_FAILED;
}
return Blockly.Connection.CAN_CONNECT;
}

/**
* Checks whether the current connection and target connection are compatible
* and throws an exception if they are not.
* @param {Blockly.Connection} target The connection to check compatibility
* with.
* @private
*/
Blockly.Connection.prototype.checkConnection_ = function(target) {
switch (this.canConnectWithReason_(target)) {
case Blockly.Connection.CAN_CONNECT:
break;
case Blockly.Connection.REASON_SELF_CONNECTION:
throw 'Attempted to connect a block to itself.';
case Blockly.Connection.REASON_DIFFERENT_WORKSPACES:
throw 'Blocks are on different workspaces.';
case Blockly.Connection.REASON_WRONG_TYPE:
throw 'Attempt to connect incompatible types.';
case Blockly.Connection.REASON_MUST_DISCONNECT:
throw 'Source connection already connected.';
case Blockly.Connection.REASON_TARGET_NULL:
throw 'Target connection is null.';
default:
throw 'Unknown connection failure: this should never happen!';
}
}

/**
* Connect this connection to another connection.
* @param {!Blockly.Connection} otherConnection Connection to connect to.
*/
Blockly.Connection.prototype.connect = function(otherConnection) {
if (this.sourceBlock_ == otherConnection.sourceBlock_) {
throw 'Attempted to connect a block to itself.';
}
if (this.sourceBlock_.workspace !== otherConnection.sourceBlock_.workspace) {
throw 'Blocks are on different workspaces.';
}
if (Blockly.OPPOSITE_TYPE[this.type] != otherConnection.type) {
throw 'Attempt to connect incompatible types.';
}
if (this.targetConnection) {
throw 'Source connection already connected.';
}
this.checkConnection_(otherConnection);
// If the previous statement failed it would have thrown an exception.

if (otherConnection.targetConnection) {
// Other connection is already connected to something.
// Disconnect it and reattach it or bump it as needed.
var orphanBlock = otherConnection.targetBlock();
// Displaced shadow blocks dissolve rather than reattaching or bumping.
if (orphanBlock.isShadow()) {
orphanBlock.dispose();
orphanBlock = null;
Expand All @@ -192,18 +248,13 @@ Blockly.Connection.prototype.connect = function(otherConnection) {
throw 'Orphan block does not have an output connection.';
}
// Attempt to reattach the orphan at the end of the newly inserted
// block. Since this block may be a row, walk down to the end.
var newBlock = this.sourceBlock_;
var connection;
while (connection = Blockly.Connection.singleConnection_(
/** @type {!Blockly.Block} */ (newBlock), orphanBlock)) {
// '=' is intentional in line above.
newBlock = connection.targetBlock();
if (!newBlock || newBlock.isShadow()) {
orphanBlock.outputConnection.connect(connection);
orphanBlock = null;
break;
}
// block. Since this block may be a row, walk down to the end
// or to the first (and only) shadow block.
var connection = Blockly.Connection.lastConnectionInRow_(
this.sourceBlock_, orphanBlock);
if (connection != null) {
orphanBlock.outputConnection.connect(connection);
orphanBlock = null;
}
} else if (this.type == Blockly.PREVIOUS_STATEMENT) {
// Statement connections.
Expand Down Expand Up @@ -237,7 +288,11 @@ Blockly.Connection.prototype.connect = function(otherConnection) {
setTimeout(function() {
// Verify orphan hasn't been deleted or reconnected (user on meth).
if (orphanBlock.workspace && !orphanBlock.getParent()) {
orphanBlock.outputConnection.bumpAwayFrom_(otherConnection);
if (orphanBlock.outputConnection) {
orphanBlock.outputConnection.bumpAwayFrom_(otherConnection);
} else if (orphanBlock.previousConnection) {
orphanBlock.previousConnection.bumpAwayFrom_(otherConnection);
}
}
}, Blockly.BUMP_DELAY);
}
Expand Down Expand Up @@ -306,6 +361,33 @@ Blockly.Connection.singleConnection_ = function(block, orphanBlock) {
return connection;
};

/**
* Walks down a row a blocks, at each stage checking if there are any
* connections that will accept the orphaned block. If at any point there
* are zero or multiple eligible connections, returns null. Otherwise
* returns the only input on the last block in the chain.
* <p/>
* Terminates early for shadow blocks.
* @param {!Blockly.Block} startBlack The block on which to start the search.
* @param {!Blockly.Block} orphanBlock The block that is looking for a home.
* @return {Blockly.Connection} The suitable connection point on the chain
* of blocks, or null.
* @private
*/
Blockly.Connection.lastConnectionInRow_ = function(startBlock, orphanBlock) {
var newBlock = startBlock;
var connection;
while (connection = Blockly.Connection.singleConnection_(
/** @type {!Blockly.Block} */ (newBlock), orphanBlock)) {
// '=' is intentional in line above.
newBlock = connection.targetBlock();
if (!newBlock || newBlock.isShadow()) {
return connection;
}
}
return null;
};

/**
* Disconnect this connection.
*/
Expand Down