parse pull specs
Ziyang Hu
2 years ago
parent
85c500bf62
commit
3fe5a4865a
@ -1,2 +1,3 @@
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pub(crate) mod attr;
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pub(crate) mod triple;
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pub(crate) mod pull;
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@ -0,0 +1,193 @@
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use anyhow::Result;
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use itertools::Itertools;
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use serde_json::{json, Map};
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use crate::data::attr::AttributeCardinality;
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use crate::data::json::JsonValue;
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use crate::data::keyword::Keyword;
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use crate::data::value::Value;
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use crate::preprocess::triple::TxError;
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use crate::runtime::transact::SessionTx;
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use crate::transact::pull::{AttrPullSpec, PullSpec, PullSpecs};
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#[derive(Debug, thiserror::Error)]
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pub enum PullError {
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#[error("cannot parse pull format {0}: {1}")]
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InvalidFormat(JsonValue, String),
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}
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impl SessionTx {
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pub(crate) fn parse_pull(&mut self, desc: &JsonValue, no_parent: bool) -> Result<PullSpecs> {
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if let Some(inner) = desc.as_array() {
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inner
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.iter()
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.map(|v| self.parse_pull_element(v, if no_parent { None } else { Some(inner) }))
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.try_collect()
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} else {
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Err(PullError::InvalidFormat(desc.clone(), "expect array".to_string()).into())
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}
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}
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pub(crate) fn parse_pull_element(
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&mut self,
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desc: &JsonValue,
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parent: Option<&Vec<JsonValue>>,
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) -> Result<PullSpec> {
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match desc {
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JsonValue::String(s) if s == "*" => Ok(PullSpec::PullAll),
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JsonValue::String(s) => {
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let input_kw = Keyword::from(s.as_ref());
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let reverse = input_kw.0.starts_with('<');
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let kw = if reverse {
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Keyword::from(input_kw.0.strip_prefix('<').unwrap())
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} else {
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input_kw.clone()
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};
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let attr = self.attr_by_kw(&kw)?.ok_or(TxError::AttrNotFound(kw))?;
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let cardinality = attr.cardinality;
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Ok(PullSpec::Attr(AttrPullSpec {
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attr,
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default_val: Value::Null,
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reverse,
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name: input_kw,
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cardinality,
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take: None,
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nested: vec![],
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recursive: false,
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recursion_limit: None,
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}))
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}
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JsonValue::Object(m) => self.parse_pull_obj(m, parent),
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v => Err(
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PullError::InvalidFormat(v.clone(), "expect string or object".to_string()).into(),
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),
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}
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}
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pub(crate) fn parse_pull_obj(
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&mut self,
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desc: &Map<String, JsonValue>,
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parent: Option<&Vec<JsonValue>>,
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) -> Result<PullSpec> {
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let mut default_val = Value::Null;
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let mut as_override = None;
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let mut take = None;
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let mut cardinality_override = None;
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let mut input_kw = None;
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let mut sub_target = vec![];
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let mut recursive = false;
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let mut recursion_limit = None;
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for (k, v) in desc {
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match k as &str {
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"_as" => {
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as_override = Some(Keyword::from(v.as_str().ok_or_else(|| {
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PullError::InvalidFormat(v.clone(), "expect string".to_string())
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})?))
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}
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"_limit" => {
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take = Some(v.as_u64().ok_or_else(|| {
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PullError::InvalidFormat(v.clone(), "expect limit".to_string())
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})? as usize)
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}
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"_cardinality" => {
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cardinality_override =
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Some(AttributeCardinality::try_from(v.as_str().ok_or_else(
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|| PullError::InvalidFormat(v.clone(), "expect string".to_string()),
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)?)?)
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}
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"_default" => default_val = Value::from(v).to_static(),
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k if !k.starts_with('_') => {
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if input_kw.is_some() {
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return Err(PullError::InvalidFormat(
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JsonValue::Object(desc.clone()),
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"only one sublevel target expected".to_string(),
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)
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.into());
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}
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input_kw = Some(Keyword::from(k));
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sub_target = {
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if let Some(arr) = v.as_array() {
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arr.clone()
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} else {
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if let Some(u) = v.as_u64() {
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recursion_limit = Some(u as usize);
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} else if *v != json!("...") {
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return Err(PullError::InvalidFormat(
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v.clone(),
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"expect array".to_string(),
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)
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.into());
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}
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let parent = parent.ok_or_else(|| {
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PullError::InvalidFormat(
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JsonValue::Object(desc.clone()),
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"cannot recurse at top level".to_string(),
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)
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})?;
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// not clear what two recursions would do
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if recursive {
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return Err(PullError::InvalidFormat(
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JsonValue::Object(desc.clone()),
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"cannot have two recursions".to_string(),
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)
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.into());
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}
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recursive = true;
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// remove self to prevent infinite recursion
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parent
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.iter()
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.filter(|p| {
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if let Some(o) = p.as_object() {
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o != desc
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} else {
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true
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}
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})
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.cloned()
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.collect_vec()
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}
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};
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}
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v => {
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return Err(PullError::InvalidFormat(
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v.into(),
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"unexpected spec key".to_string(),
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)
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.into())
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}
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}
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}
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if input_kw.is_none() {
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return Err(PullError::InvalidFormat(
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JsonValue::Object(desc.clone()),
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"expect target key".to_string(),
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)
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.into());
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}
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let input_kw = input_kw.unwrap();
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// let recurse_target = sub_target.unwrap();
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let reverse = input_kw.0.starts_with('<');
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let kw = if reverse {
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Keyword::from(input_kw.0.strip_prefix('<').unwrap())
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} else {
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input_kw.clone()
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};
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let attr = self.attr_by_kw(&kw)?.ok_or(TxError::AttrNotFound(kw))?;
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let cardinality = cardinality_override.unwrap_or(attr.cardinality);
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let nested = self.parse_pull(&JsonValue::Array(sub_target), recursive)?;
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Ok(PullSpec::Attr(AttrPullSpec {
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attr,
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default_val,
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reverse,
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name: as_override.unwrap_or(input_kw),
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cardinality,
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take,
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nested,
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recursive,
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recursion_limit,
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}))
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}
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}
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