arg("page", com.facebook.presto.operator.Page.class),
arg("pageBuilder", PageBuilder.class));
CompilerContext compilerContext = filterAndProjectMethod.getCompilerContext();
LocalVariableDefinition positionVariable = compilerContext.declareVariable(int.class, "position");
LocalVariableDefinition rowsVariable = compilerContext.declareVariable(int.class, "rows");
filterAndProjectMethod.getBody()
.comment("int rows = page.getPositionCount();")
.getVariable("page")
.invokeVirtual(com.facebook.presto.operator.Page.class, "getPositionCount", int.class)
.putVariable(rowsVariable);
List<LocalVariableDefinition> cursorVariables = new ArrayList<>();
int channels = getMaxInputChannel(expressionTypes) + 1;
for (int i = 0; i < channels; i++) {
LocalVariableDefinition cursorVariable = compilerContext.declareVariable(BlockCursor.class, "cursor_" + i);
cursorVariables.add(cursorVariable);
filterAndProjectMethod.getBody()
.comment("BlockCursor %s = page.getBlock(%s).cursor();", cursorVariable.getName(), i)
.getVariable("page")
.push(i)
.invokeVirtual(com.facebook.presto.operator.Page.class, "getBlock", com.facebook.presto.spi.block.Block.class, int.class)
.invokeInterface(com.facebook.presto.spi.block.Block.class, "cursor", BlockCursor.class)
.putVariable(cursorVariable);
}
//
// for loop body
//
// for (position = 0; position < rows; position++)
ForLoopBuilder forLoop = forLoopBuilder(compilerContext)
.comment("for (position = 0; position < rows; position++)")
.initialize(new Block(compilerContext).putVariable(positionVariable, 0))
.condition(new Block(compilerContext)
.getVariable(positionVariable)
.getVariable(rowsVariable)
.invokeStatic(CompilerOperations.class, "lessThan", boolean.class, int.class, int.class))
.update(new Block(compilerContext).incrementVariable(positionVariable, (byte) 1));
Block forLoopBody = new Block(compilerContext);
// cursor.advanceNextPosition()
for (LocalVariableDefinition cursorVariable : cursorVariables) {
forLoopBody
.comment("checkState(%s.advanceNextPosition());", cursorVariable.getName())
.getVariable(cursorVariable)
.invokeInterface(BlockCursor.class, "advanceNextPosition", boolean.class)
.invokeStatic(Preconditions.class, "checkState", void.class, boolean.class);
}
IfStatementBuilder ifStatement = new IfStatementBuilder(compilerContext)
.comment("if (filter(cursors...)");
Block condition = new Block(compilerContext);
condition.pushThis();
for (int channel = 0; channel < channels; channel++) {
condition.getVariable("cursor_" + channel);
}
condition.invokeVirtual(classDefinition.getType(), "filter", type(boolean.class), nCopies(channels, type(BlockCursor.class)));
ifStatement.condition(condition);
Block trueBlock = new Block(compilerContext);
if (projections.isEmpty()) {
trueBlock
.comment("pageBuilder.declarePosition()")
.getVariable("pageBuilder")
.invokeVirtual(PageBuilder.class, "declarePosition", void.class);
}
else {
// pageBuilder.getBlockBuilder(0).append(cursor.getDouble(0);
for (int projectionIndex = 0; projectionIndex < projections.size(); projectionIndex++) {
trueBlock.comment("project_%s(cursors..., pageBuilder.getBlockBuilder(%s))", projectionIndex, projectionIndex);
trueBlock.pushThis();
for (int channel = 0; channel < channels; channel++) {
trueBlock.getVariable("cursor_" + channel);
}
// pageBuilder.getBlockBuilder(0)
trueBlock.getVariable("pageBuilder")
.push(projectionIndex)
.invokeVirtual(PageBuilder.class, "getBlockBuilder", BlockBuilder.class, int.class);
// project(cursor_0, cursor_1, blockBuilder)
trueBlock.invokeVirtual(classDefinition.getType(),
"project_" + projectionIndex,
type(void.class),
ImmutableList.<ParameterizedType>builder().addAll(nCopies(channels, type(BlockCursor.class))).add(type(BlockBuilder.class)).build());
}
}
ifStatement.ifTrue(trueBlock);
forLoopBody.append(ifStatement.build());
filterAndProjectMethod.getBody().append(forLoop.body(forLoopBody).build());
//
// Verify all cursors ended together
//
// checkState(!cursor.advanceNextPosition());
for (LocalVariableDefinition cursorVariable : cursorVariables) {
filterAndProjectMethod.getBody()
.comment("checkState(not(%s.advanceNextPosition))", cursorVariable.getName())
.getVariable(cursorVariable)
.invokeInterface(BlockCursor.class, "advanceNextPosition", boolean.class)
.invokeStatic(CompilerOperations.class, "not", boolean.class, boolean.class)
.invokeStatic(Preconditions.class, "checkState", void.class, boolean.class);
}