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//! DeepMerge implementation for serde_json::Value
use crate::policy::*;
use crate::{DeepMerge, MergeOutcome};
use serde_json::Value;
use std::mem;
impl<P: Policy> DeepMerge<P> for Value {
fn merge_with_policy(&mut self, other: Self, policy: &P) {
// Check condition early
match policy.when_condition() {
Condition::Always => {},
Condition::NonEmpty => {
match &other {
Value::Null => return,
Value::Array(arr) if arr.is_empty() => return,
Value::Object(obj) if obj.is_empty() => return,
Value::String(s) if s.is_empty() => return,
_ => {},
}
},
Condition::NonDefault => {
match &other {
Value::Null => return,
Value::Bool(false) => return,
Value::Number(n) if n.as_i64() == Some(0) || n.as_f64() == Some(0.0) => return,
Value::String(s) if s.is_empty() => return,
Value::Array(arr) if arr.is_empty() => return,
Value::Object(obj) if obj.is_empty() => return,
_ => {},
}
},
Condition::Some => {
if matches!(other, Value::Null) {
return;
}
},
Condition::Changed => {
if self == &other {
return;
}
},
Condition::ChangedBy(_) => {
// Without custom key extractors, fall back to equality
if self == &other {
return;
}
},
}
// Apply merge based on types
match (self, other) {
// Object merging uses map policies
(Value::Object(dst), Value::Object(src)) => {
match policy.map_merge() {
MapMerge::Overlay => {
// Recursively merge matching keys, add new keys
for (k, v) in src.into_iter() {
match dst.get_mut(&k) {
Some(dst_val) => {
dst_val.merge_with_policy(v, policy);
},
None => {
dst.insert(k, v);
}
}
}
},
MapMerge::Union => {
// Add all keys from src, overwriting on conflict
dst.extend(src);
},
MapMerge::Left => {
// Keep only left entries
},
MapMerge::Right => {
// Replace with right entries
*dst = src;
},
}
},
// Array merging uses sequence policies
(Value::Array(dst), Value::Array(src)) => {
match policy.sequence_merge() {
SequenceMerge::Append | SequenceMerge::Extend => {
dst.extend(src);
},
SequenceMerge::Prepend => {
let mut result = src;
result.extend(mem::take(dst));
*dst = result;
},
SequenceMerge::Union => {
// O(n^2) deduplication by equality - acceptable for config-sized arrays
for v in src {
if !dst.iter().any(|existing| existing == &v) {
dst.push(v);
}
}
},
SequenceMerge::Intersect => {
// Keep only elements that exist in both
let src_set = &src; // Keep reference for comparison
dst.retain(|x| src_set.iter().any(|y| y == x));
},
}
},
// String merging uses string policies
(Value::String(dst), Value::String(src)) => {
match policy.string_merge() {
StringMerge::Replace => *dst = src,
StringMerge::Keep => {},
StringMerge::Concat => dst.push_str(&src),
StringMerge::ConcatWithSep(sep) => {
if !dst.is_empty() && !src.is_empty() {
dst.push_str(sep);
}
dst.push_str(&src);
},
}
},
// Boolean merging uses bool policies
(Value::Bool(dst), Value::Bool(src)) => {
match policy.bool_merge() {
BoolMerge::Replace => *dst = src,
BoolMerge::Keep => {},
BoolMerge::TrueWins => *dst = *dst || src,
BoolMerge::FalseWins => *dst = *dst && src,
}
},
// Number merging uses number policies
(Value::Number(dst), Value::Number(src)) => {
match policy.number_merge() {
NumberMerge::Replace => *dst = src,
NumberMerge::Keep => {},
NumberMerge::Sum => {
// Try integer addition first, fall back to float
if let (Some(a), Some(b)) = (dst.as_i64(), src.as_i64()) {
*dst = serde_json::Number::from(a.saturating_add(b));
} else if let (Some(a), Some(b)) = (dst.as_f64(), src.as_f64()) {
if let Some(num) = serde_json::Number::from_f64(a + b) {
*dst = num;
}
}
},
NumberMerge::Max => {
if let (Some(a), Some(b)) = (dst.as_f64(), src.as_f64()) {
if b > a {
*dst = src;
}
}
},
NumberMerge::Min => {
if let (Some(a), Some(b)) = (dst.as_f64(), src.as_f64()) {
if b < a {
*dst = src;
}
}
},
}
},
// Mismatched types or Null: use scalar action
(dst, src) => {
match policy.scalar_action() {
ScalarAction::Replace => *dst = src,
ScalarAction::Keep => {},
ScalarAction::Merge => {
// For incompatible types, merge means replace
*dst = src;
}
}
}
}
}
fn merge_with_policy_reporting(&mut self, other: Self, policy: &P) -> MergeOutcome {
// Check if values are equal before merging
let unchanged = self == &other;
// Check condition early
match policy.when_condition() {
Condition::Always => {},
Condition::NonEmpty => {
match &other {
Value::Null => return MergeOutcome::Unchanged,
Value::Array(arr) if arr.is_empty() => return MergeOutcome::Unchanged,
Value::Object(obj) if obj.is_empty() => return MergeOutcome::Unchanged,
Value::String(s) if s.is_empty() => return MergeOutcome::Unchanged,
_ => {},
}
},
Condition::NonDefault => {
match &other {
Value::Null => return MergeOutcome::Unchanged,
Value::Bool(false) => return MergeOutcome::Unchanged,
Value::Number(n) if n.as_i64() == Some(0) || n.as_f64() == Some(0.0) => {
return MergeOutcome::Unchanged;
},
Value::String(s) if s.is_empty() => return MergeOutcome::Unchanged,
Value::Array(arr) if arr.is_empty() => return MergeOutcome::Unchanged,
Value::Object(obj) if obj.is_empty() => return MergeOutcome::Unchanged,
_ => {},
}
},
Condition::Some => {
if matches!(other, Value::Null) {
return MergeOutcome::Unchanged;
}
},
Condition::Changed => {
if unchanged {
return MergeOutcome::Unchanged;
}
},
Condition::ChangedBy(_) => {
if unchanged {
return MergeOutcome::Unchanged;
}
},
}
// Store original for comparison
let original = self.clone();
// Perform merge
self.merge_with_policy(other, policy);
// Check if anything changed
if &original == self {
MergeOutcome::Unchanged
} else {
MergeOutcome::Changed
}
}
}