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Small refactor for printing conditions
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Reviewed By: kassens

Differential Revision: D20069492

fbshipit-source-id: 0a22d9d94e4e18ef9124ba7bfe6727122559e491
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Juan Tejada authored and facebook-github-bot committed Feb 25, 2020
1 parent 86f5456 commit bfabdf9
Showing 1 changed file with 65 additions and 50 deletions.
115 changes: 65 additions & 50 deletions compiler/crates/graphql-printer/src/printer.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -127,7 +127,7 @@ impl<'schema, 'writer, W: Write> Printer<'schema, 'writer, W> {
write!(self.writer, "{} {}", operation_kind, operation_name)?;
self.print_variable_definitions(&operation.variable_definitions)?;
self.print_directives(&operation.directives, None)?;
self.print_selections(&operation.selections, None, 0)
self.print_selections(&operation.selections, 0)
}

fn print_fragment(mut self, fragment: &FragmentDefinition) -> Result {
Expand All @@ -141,7 +141,29 @@ impl<'schema, 'writer, W: Write> Printer<'schema, 'writer, W> {
.unwrap();
self.print_argument_definitions(&fragment.variable_definitions)?;
self.print_directives(&fragment.directives, None)?;
self.print_selections(&fragment.selections, None, 0)
self.print_selections(&fragment.selections, 0)
}

fn print_selections(&mut self, selections: &[Selection], indent_count: usize) -> Result {
let len = selections.len();
if len > 0 {
let next_indent_count = indent_count + TAB_SIZE;
writeln!(self.writer, " {{")?;
self.print_indentation(next_indent_count)?;

for (i, selection) in selections.iter().enumerate() {
self.print_selection(selection, None, next_indent_count)?;
if i != len - 1 {
writeln!(self.writer)?;
self.print_indentation(next_indent_count)?;
}
}

writeln!(self.writer)?;
self.print_indentation(indent_count)?;
write!(self.writer, "}}")?;
}
Ok(())
}

fn print_selection(
Expand All @@ -164,39 +186,12 @@ impl<'schema, 'writer, W: Write> Printer<'schema, 'writer, W> {
self.print_inline_fragment(field, conditions, indent_count)?;
}
Selection::Condition(field) => {
self.print_condition(field, conditions, indent_count)?;
self.print_condition(field, indent_count)?;
}
}
Ok(())
}

fn print_selections(
&mut self,
selections: &[Selection],
conditions: Option<&[Condition]>,
indent_count: usize,
) -> Result {
let len = selections.len();
if len > 0 {
let next_indent_count = indent_count + TAB_SIZE;
writeln!(self.writer, " {{")?;
self.print_indentation(next_indent_count)?;

for (i, selection) in selections.iter().enumerate() {
self.print_selection(selection, conditions, next_indent_count)?;
if i != len - 1 {
writeln!(self.writer)?;
self.print_indentation(next_indent_count)?;
}
}

writeln!(self.writer)?;
self.print_indentation(indent_count)?;
write!(self.writer, "}}")?;
}
Ok(())
}

fn print_scalar_field(
&mut self,
field: &ScalarField,
Expand All @@ -220,7 +215,7 @@ impl<'schema, 'writer, W: Write> Printer<'schema, 'writer, W> {
write!(self.writer, "{}", schema_field.name)?;
self.print_arguments(&field.arguments)?;
self.print_directives(&field.directives, conditions)?;
self.print_selections(&field.selections, None, indent_count)?;
self.print_selections(&field.selections, indent_count)?;
Ok(())
}

Expand Down Expand Up @@ -249,27 +244,47 @@ impl<'schema, 'writer, W: Write> Printer<'schema, 'writer, W> {
)?;
};
self.print_directives(&field.directives, conditions)?;
self.print_selections(&field.selections, None, indent_count)
self.print_selections(&field.selections, indent_count)
}

fn print_condition(
&mut self,
condition: &Condition,
parent_conditions: Option<&[Condition]>,
indent_count: usize,
) -> Result {
let len = condition.selections.len();
for (i, selection) in condition.selections.iter().enumerate() {
let next_conditions: Vec<Condition> = match parent_conditions {
Some(parent_conditions) => {
let mut next_conditions: Vec<Condition> = vec![condition.clone()];
next_conditions.extend(parent_conditions.iter().cloned());
next_conditions
fn print_condition(&mut self, condition: &Condition, indent_count: usize) -> Result {
let mut maybe_current_condition = Some(condition);
let mut accum_conditions: Vec<Condition> = vec![];
let mut selections: Vec<&Selection> = vec![];

// Extract all nested conditions into a flattened list of conditions, and
// extract the selections from the "leaf" condition
while let Some(current_condition) = maybe_current_condition {
accum_conditions.push(current_condition.clone());

if current_condition.selections.len() == 1 {
let selection = &current_condition.selections[0];
if let Selection::Condition(nested_cond) = selection {
maybe_current_condition = Some(&nested_cond);
} else {
selections.push(&selection);
maybe_current_condition = None;
}
} else {
for selection in current_condition.selections.iter() {
if let Selection::Condition(_) = selection {
unreachable!("Expected for a Condition to contain either a single Condition node, or non-Condition selections.");
}
selections.push(selection);
}
None => vec![condition.clone()],
};
maybe_current_condition = None;
}
}
accum_conditions.reverse();

self.print_selection(&selection, Some(&next_conditions), indent_count)?;
// We don't call print_selections here because the selections for a condition (or set of conditions)
// aren't printed in the same way. Specifically, we don't need to print curly braces around them
// and we don't need to increase the indentation. Instead, the output of printing a condition node will
// expand into printing selections as children of the current parent, with all the relevant
// condition directives included in each selection.
let len = selections.len();
for (i, selection) in selections.iter().enumerate() {
self.print_selection(&selection, Some(&accum_conditions), indent_count)?;
if i != len - 1 {
writeln!(self.writer)?;
self.print_indentation(indent_count)?;
Expand All @@ -289,12 +304,12 @@ impl<'schema, 'writer, W: Write> Printer<'schema, 'writer, W> {
self.print_arguments(&directive.arguments)?;
}
if let Some(conditions) = conditions {
self.print_conditions(conditions)?;
self.print_condition_directives(conditions)?;
}
Ok(())
}

fn print_conditions(&mut self, conditions: &[Condition]) -> Result {
fn print_condition_directives(&mut self, conditions: &[Condition]) -> Result {
for condition in conditions {
write!(
self.writer,
Expand Down

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