Skip to content

Commit

Permalink
Merge pull request #764 from plokhotnyuk/more-efficient-parsing-of-JS…
Browse files Browse the repository at this point in the history 
…ON-objects-and-arrays

More efficient parsing of json objects and arrays
  • Loading branch information
@Baccata
Baccata authored Jan 30, 2023
2 parents 24589c1 + eb025bb commit f81b362
Show file tree
Hide file tree
Showing 2 changed files with 92 additions and 50 deletions.
84 changes: 52 additions & 32 deletions modules/json/src/smithy4s/http/json/Cursor.scala
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,78 +22,98 @@ import com.github.plokhotnyuk.jsoniter_scala.core.JsonReaderException
import smithy4s.http.PayloadError

class Cursor private () {
private[this] var stack: Array[PayloadPath.Segment] =
new Array[PayloadPath.Segment](8)
private[this] var top: Int = 0
private var expecting: String = null
private[this] var indexStack: Array[Int] = new Array[Int](8)
private[this] var labelStack: Array[String] = new Array[String](8)
private[this] var top: Int = _
private var expecting: String = _

def decode[A](codec: JCodec[A], in: JsonReader): A = {
this.expecting = codec.expecting
codec.decodeValue(this, in)
}

def under[A](segment: PayloadPath.Segment)(f: => A): A = {
if (top >= stack.length) stack = java.util.Arrays.copyOf(stack, top << 1)
stack(top) = segment
top += 1
def under[A](segment: PayloadPath.Segment)(f: => A): A =
segment match {
case i: PayloadPath.Segment.Index => under(i.index)(f)
case l: PayloadPath.Segment.Label => under(l.label)(f)
}

def under[A](label: String)(f: => A): A = {
push(label)
val res = f
top -= 1
pop()
res
}

def under[A](label: String)(f: => A): A =
under(new PayloadPath.Segment.Label(label))(f)
def under[A](index: Int)(f: => A): A = {
push(index)
val res = f
pop()
res
}

def under[A](index: Int)(f: => A): A =
under(new PayloadPath.Segment.Index(index))(f)
def push(label: String): Unit = {
if (top >= labelStack.length) growStacks()
labelStack(top) = label
top += 1
}

def push(index: Int): Unit = {
if (top >= indexStack.length) growStacks()
indexStack(top) = index
top += 1
}

def pop(): Unit = top -= 1

def payloadError[A](codec: JCodec[A], message: String): Nothing =
throw PayloadError(getPath(), codec.expecting, message)
throw new PayloadError(getPath(Nil), codec.expecting, message)

def requiredFieldError[A](codec: JCodec[A], field: String): Nothing =
requiredFieldError(codec.expecting, field)

def requiredFieldError[A](expecting: String, field: String): Nothing = {
var top = this.top
if (top >= stack.length) stack = java.util.Arrays.copyOf(stack, top << 1)
stack(top) = new PayloadPath.Segment.Label(field)
top += 1
var list: List[PayloadPath.Segment] = Nil
while (top > 0) {
top -= 1
list = stack(top) :: list
}
throw PayloadError(PayloadPath(list), expecting, "Missing required field")
val path = getPath(new PayloadPath.Segment.Label(field) :: Nil)
throw new PayloadError(path, expecting, "Missing required field")
}

private def getPath(): PayloadPath = {
private def getPath(segments: List[PayloadPath.Segment]): PayloadPath = {
var top = this.top
var list: List[PayloadPath.Segment] = Nil
var list = segments
while (top > 0) {
top -= 1
list = stack(top) :: list
val label = labelStack(top)
val segment =
if (label ne null) new PayloadPath.Segment.Label(label)
else new PayloadPath.Segment.Index(indexStack(top))
list = segment :: list
}
PayloadPath(list)
new PayloadPath(list)
}

private def getExpected(): String =
if (expecting != null) expecting
else throw new IllegalStateException("Expected should have been fulfilled")

private[this] def growStacks(): Unit = {
val size = top << 1
labelStack = java.util.Arrays.copyOf(labelStack, size)
indexStack = java.util.Arrays.copyOf(indexStack, size)
}
}

object Cursor {

def withCursor[A](expecting: String)(f: Cursor => A): A = {
val cursor = new Cursor()
cursor.expecting = expecting
try {
f(cursor)
} catch {
try f(cursor)
catch {
case e: JsonReaderException => payloadError(cursor, e.getMessage())
case e: ConstraintError => payloadError(cursor, e.message)
}
}

private[this] def payloadError(cursor: Cursor, message: String): Nothing =
throw PayloadError(cursor.getPath(), cursor.getExpected(), message)
throw new PayloadError(cursor.getPath(Nil), cursor.getExpected(), message)
}
58 changes: 40 additions & 18 deletions modules/json/src/smithy4s/http/json/SchemaVisitorJCodec.scala
View file
Original file line number Diff line number Diff line change
Expand Up @@ -462,7 +462,9 @@ private[smithy4s] class SchemaVisitorJCodec(
var i = 0
while ({
if (i >= maxArity) maxArityError(cursor)
builder += cursor.under(i)(cursor.decode(a, in))
cursor.push(i)
builder += cursor.decode(a, in)
cursor.pop()
i += 1
in.isNextToken(',')
}) ()
Expand Down Expand Up @@ -512,7 +514,9 @@ private[smithy4s] class SchemaVisitorJCodec(
var i = 0
while ({
if (i >= maxArity) maxArityError(cursor)
builder += cursor.under(i)(cursor.decode(a, in))
cursor.push(i)
builder += cursor.decode(a, in)
cursor.pop()
i += 1
in.isNextToken(',')
}) ()
Expand Down Expand Up @@ -559,7 +563,9 @@ private[smithy4s] class SchemaVisitorJCodec(
var i = 0
while ({
if (i >= maxArity) maxArityError(cursor)
put(cursor.under(i)(cursor.decode(a, in)))
cursor.push(i)
put(cursor.decode(a, in))
cursor.pop()
i += 1
in.isNextToken(',')
}) ()
Expand Down Expand Up @@ -616,7 +622,9 @@ private[smithy4s] class SchemaVisitorJCodec(
var i = 0
while ({
if (i >= maxArity) maxArityError(cursor)
builder += cursor.under(i)(cursor.decode(a, in))
cursor.push(i)
builder += cursor.decode(a, in)
cursor.pop()
i += 1
in.isNextToken(',')
}) ()
Expand Down Expand Up @@ -663,8 +671,12 @@ private[smithy4s] class SchemaVisitorJCodec(
if (i >= maxArity) maxArityError(cursor)
builder += (
(
jk.decodeKey(in),
cursor.under(i)(cursor.decode(jv, in))
jk.decodeKey(in), {
cursor.push(i)
val result = cursor.decode(jv, in)
cursor.pop()
result
}
)
)
i += 1
Expand Down Expand Up @@ -798,11 +810,11 @@ private[smithy4s] class SchemaVisitorJCodec(
else {
in.rollbackToken()
val key = in.readKeyAsString()
val result = cursor.under(key) {
val handler = handlerMap.get(key)
if (handler eq null) in.discriminatorValueError(key)
handler(cursor, in)
}
cursor.push(key)
val handler = handlerMap.get(key)
if (handler eq null) in.discriminatorValueError(key)
val result = handler(cursor, in)
cursor.pop()
if (in.isNextToken('}')) result
else {
in.rollbackToken()
Expand Down Expand Up @@ -931,11 +943,12 @@ private[smithy4s] class SchemaVisitorJCodec(
val key = in.readString("")
in.rollbackToMark()
in.rollbackToken()
cursor.under(key) {
val handler = handlerMap.get(key)
if (handler eq null) in.discriminatorValueError(key)
handler(cursor, in)
}
cursor.push(key)
val handler = handlerMap.get(key)
if (handler eq null) in.discriminatorValueError(key)
val result = handler(cursor, in)
cursor.pop()
result
} else
in.decodeError(
s"Unable to find discriminator ${discriminated.value}"
Expand Down Expand Up @@ -1071,14 +1084,23 @@ private[smithy4s] class SchemaVisitorJCodec(
val codec = apply(field.instance)
val label = field.label
if (field.isRequired) { (cursor, in, mmap) =>
val _ = mmap.put(label, cursor.under(label)(cursor.decode(codec, in)))
val _ = mmap.put(
label, {
cursor.push(label)
val result = cursor.decode(codec, in)
cursor.pop()
result
}
)
} else { (cursor, in, mmap) =>
cursor.under[Unit](label) {
{
cursor.push(label)
if (in.isNextToken('n')) in.readNullOrError[Unit]((), "Expected null")
else {
in.rollbackToken()
val _ = mmap.put(label, cursor.decode(codec, in))
}
cursor.pop()
}
}
}
Expand Down

0 comments on commit f81b362

Please sign in to comment.