BufferScopeTracker.java
/*
** Module : BufferScopeTracker.java
** Abstract : contains data and methods to manage the buffer scoping to a
** specific block and the list of associated schema references
**
** Copyright (c) 2005-2022, Golden Code Development Corporation.
**
** -#- -I- --Date-- --JPRM-- -----------------------------------Description-----------------------------------
** 001 GES 20050921 @22786 First version which provides a helper class which can be easily used
** from a rule set. This class contains data and methods to manage the
** buffer scoping to a specific block and the list of associated schema
** references.
** 002 GES 20090518 @42376 Import change.
** 003 OM 20161011 nearestRecordScopingBlock() takes into account type and location of
** the buffer to match the P4GL buffer scoping. Added generics.
** 004 CA 20220613 'nearestRecordScopingBlock' must consider the OO blocks, too (constructor, method,
** property block, destructor).
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
** are non-permissive additional terms allowed under Section 7 of the GNU
** Affero GPL version 3 and may not be removed by you.
**
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**
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*/
package com.goldencode.p2j.convert;
import java.util.*;
import com.goldencode.ast.*;
import com.goldencode.p2j.uast.*;
/**
* This class contains the data and helper methods to implement/manage the
* buffer scoping process during conversion. Each instance of a buffer will
* correspond with an instance of this class. More than one instance may
* exist for a given buffer name in a given AST. Each instance contains
* the knowledge of the specific block to which it is scoped as well as the
* list of all associated schema references which use this buffer.
*/
public class BufferScopeTracker
implements ProgressParserTokenTypes
{
/** The list of {@code Aast} nodes which use this buffer. */
private Set<Aast> refNodes = null;
/** The {@code Aast} node to which this buffer is scoped. */
private Aast block = null;
/** The type of the scope. */
private int type = -1;
/**
* Create an instance to track a buffer scope of a given buffer name.
*
* @param type
* The token type representing the type of reference being
* represented (strong, weak or free).
*/
public BufferScopeTracker(int type)
{
setType(type);
refNodes = new HashSet<>();
}
/**
* Add the given AST node to the list of references to this buffer scope.
* <p>
* This method does not modify or set the block node to which the buffer
* is scoped. For that, use {@link #setScopeBlock}.
*
* @param ast
* The node in the AST that references the buffer.
*/
public void addReference(Aast ast)
{
if (!refNodes.isEmpty())
{
setType(EXPANDED_SCOPE);
}
refNodes.add(ast);
}
/**
* Add the given AST node to the list of references to this buffer scope
* and update the block node to the nearest enclosing AST node which has
* the record scoping property. This assumes that the <code>block</code>
* member is a valid AST node.
*
* @param ast
* The node in the AST that references the buffer.
*/
public void mergeReference(Aast ast)
{
// is our block already the root node?
if (!block.isRoot())
{
// find the nearest enclosing block
Aast nearest = block.nearestEnclosing(ast);
// walk up to find a block with record scoping, set the enclosing block
block = nearestRecordScopingBlock(nearest, false);
}
// add the reference
addReference(ast);
}
/**
* Search up the tree from the given AST node to find the first block node that also has the
* {@code recordScoping} property. Note that if the given node is of type {@code BLOCK} and
* this node has the {@code recordScoping} property, then the given node amy be returned.
* <p>
* The search takes into consideration the type of the buffer (whether it was explicitly
* created) and the block location (whether the buffer usage is inside an internal procedure,
* function or database trigger). In the case of implicit buffers in these location the free
* references and weak references will create scopes in the main procedure (external). This
* method assumes the strong references are always using explicit buffers for these locations.
* Using an implicit buffer in a procedure is an error (3503) in 4GL.
*
* This code assumes that only {@code BLOCK} nodes can have the {@code recordScoping} property.
*
* @param ast
* The AST node from which to search upward.
* @param implicit
* Whether the buffer for this search is not explicit. In this case, if the current
* block is included in a procedure, the scope is the one of the external procedure
* instead of the local one.
*
* @return A block node with the {@code recordScoping} property (this should never be
* {@code null} since the root node of every tree meets this criteria at a minimum.
*/
public Aast nearestRecordScopingBlock(Aast ast, boolean implicit)
{
// for non strong-scopes not explicitly/locally defined in a procedure/function/trigger we
// use the external procedure scope.
// (strong-scope buffers MUST be explicitly created inside a procedure/function/trigger)
if (implicit)
{
Aast pAst = ast.getAncestor(-1, PROCEDURE);
if (pAst == null)
{
pAst = ast.getAncestor(-1, FUNCTION);
}
if (pAst == null)
{
pAst = ast.getAncestor(-1, CONSTRUCTOR);
}
if (pAst == null)
{
pAst = ast.getAncestor(-1, DEFINE_PROPERTY);
}
if (pAst == null)
{
pAst = ast.getAncestor(-1, METHOD_DEF);
}
if (pAst == null)
{
pAst = ast.getAncestor(-1, DESTRUCTOR);
}
if (pAst == null)
{
pAst = ast.getAncestor(-1, TRIGGER_BLOCK);
}
if (pAst != null)
{
ast = pAst.getParent();
}
}
Boolean recordProp = (Boolean) ast.getAnnotation("recordScoping");
// manually work up the tree from there until the block node with the record scoping
// property is found (this will at least be the root node so it should never be null)
while (recordProp == null || !recordProp)
{
// get the next node
ast = ast.getParent();
// check integrity
if (ast == null)
{
throw new RuntimeException(
"This source tree is missing 'recordScoping' annotations!");
}
recordProp = (Boolean) ast.getAnnotation("recordScoping");
}
// safety first
if (ast.getType() != BLOCK)
{
throw new RuntimeException("Expecting a BLOCK node and found a " +
ast.toString() + " instead.");
}
return ast;
}
/**
* Returns an iterator to the list of reference nodes. Each node is of
* type <code>Aast</code>.
*
* @return An iterator to all reference nodes.
*/
public Iterator getReferenceList()
{
return refNodes.iterator();
}
/**
* Scopes this buffer to a specific block AST node. This method uses the
* {@link #nearestRecordScopingBlock} method to check and find (if needed)
* the nearest enclosing block that contains the record scoping property.
* If the given AST node is of type <code>BLOCK</code> and has the record
* scoping property, then this value is set. Otherwise, this will search
* up the tree from this given node to find the first qualifying block.
*
* @param block
* The block AST node to which this buffer is scoped OR the AST node at which to
* start the search.
* @param implicit
* {@code true} if the the analysed buffer is implicit defined.
*/
public void setScopeBlock(Aast block, boolean implicit)
{
this.block = nearestRecordScopingBlock(block, implicit);
}
/**
* Gets the specific block AST node to which this buffer is scoped.
*
* @return The block AST node to which this buffer is scoped.
*/
public Aast getScopeBlock()
{
return block;
}
/**
* Sets the Progress token type describing the scope.
*
* @param type
* One of the following: {@code STRONG_REFERENCE}, {@code WEAK_REFERENCE},
* {@code FREE_REFERENCE} or {@code EXPANDED_SCOPE}.
*/
public void setType(int type)
{
if (type == STRONG_REFERENCE || type == WEAK_REFERENCE ||
type == FREE_REFERENCE || type == EXPANDED_SCOPE )
{
this.type = type;
}
}
/**
* Accesses the Progress token type describing the scope.
*
* @return One of the following: <code>STRONG_REFERENCE</code>,
* <code>WEAK_REFERENCE</code>, <code>FREE_REFERENCE</code> or
* <code>EXPANDED_SCOPE</code>.
*/
public int getType()
{
return type;
}
/**
* Adds all of the nodes in the given tracker's list of references to this
* tracker's reference list. No state is changed in the passed tracker.
* <p>
* This method does not modify or set the block node to which the buffer
* is scoped. For that, use {@link #setScopeBlock}.
*
* @param bst
* The tracker from which to copy the references.
*/
public void combine(BufferScopeTracker bst)
{
// merge the references
refNodes.addAll(bst.refNodes);
// set the type
setType(EXPANDED_SCOPE);
}
}