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1704 lines (1445 loc) · 64.4 KB
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/*
* Copyright 2018-2020 Redis Labs Ltd. and Contributors
*
* This file is available under the Redis Labs Source Available License Agreement
*/
#include "ast.h"
#include "ast_shared.h"
#include "../util/arr.h"
#include "cypher_whitelist.h"
#include "../procedures/procedure.h"
#include "../arithmetic/repository.h"
#include "../arithmetic/arithmetic_expression.h"
#include <assert.h>
#include "../util/rax_extensions.h"
#include "../query_ctx.h"
// Forward declaration
static void _AST_GetDefinedIdentifiers(const cypher_astnode_t *node, rax *identifiers);
inline static void _prepareIterateAll(rax *map, raxIterator *iter) {
raxStart(iter, map);
raxSeek(iter, "^", NULL, 0);
}
// Validate that an input string can be completely converted to a positive integer in range.
static inline AST_Validation _ValidatePositiveInteger(const char *input) {
assert(input);
char *endptr; // If the entire string is converted, endptr will point to a null byte
errno = 0; // If underflow or overflow occurs, errno will be set
strtol(input, &endptr, 0); // Perform conversion
if(errno != 0 || *endptr != '\0') return AST_INVALID;
return AST_VALID;
}
static void _AST_GetIdentifiers(const cypher_astnode_t *node, rax *identifiers) {
if(!node) return;
assert(identifiers);
if(cypher_astnode_type(node) == CYPHER_AST_IDENTIFIER) {
const char *identifier = cypher_ast_identifier_get_name(node);
raxInsert(identifiers, (unsigned char *)identifier, strlen(identifier), NULL, NULL);
}
uint child_count = cypher_astnode_nchildren(node);
/* In case current node is of type projection
* inspect first child only,
* @10 20..26 > > > projection expression=@11, alias=@14
* @11 20..26 > > > > apply @12(@13)
* @12 20..23 > > > > > function name `max`
* @13 24..25 > > > > > identifier `z`
* @14 20..26 > > > > identifier `max(z)` */
cypher_astnode_type_t type = cypher_astnode_type(node);
if(type == CYPHER_AST_PROJECTION) child_count = 1;
for(uint i = 0; i < child_count; i++) {
const cypher_astnode_t *child = cypher_astnode_get_child(node, i);
_AST_GetIdentifiers(child, identifiers);
}
if(type == CYPHER_AST_LIST_COMPREHENSION || type == CYPHER_AST_ANY || type == CYPHER_AST_ALL) {
// A list comprehension has a local variable that should only be accessed within its scope;
// do not leave it in the identifiers map.
const cypher_astnode_t *variable_node = cypher_ast_list_comprehension_get_identifier(node);
const char *variable = cypher_ast_identifier_get_name(variable_node);
raxRemove(identifiers, (unsigned char *)variable, strlen(variable), NULL);
}
}
static void _AST_GetWithAliases(const cypher_astnode_t *node, rax *aliases) {
if(!node) return;
if(cypher_astnode_type(node) != CYPHER_AST_WITH) return;
assert(aliases);
uint num_with_projections = cypher_ast_with_nprojections(node);
for(uint i = 0; i < num_with_projections; i ++) {
const cypher_astnode_t *child = cypher_ast_with_get_projection(node, i);
const cypher_astnode_t *alias_node = cypher_ast_projection_get_alias(child);
const char *alias;
if(alias_node) {
alias = cypher_ast_identifier_get_name(alias_node);
} else {
const cypher_astnode_t *expr = cypher_ast_projection_get_expression(child);
// This expression not being an identifier is an error case, but will be captured in a later validation.
if(cypher_astnode_type(expr) != CYPHER_AST_IDENTIFIER) continue;
// Retrieve "a" from "WITH a"
alias = cypher_ast_identifier_get_name(expr);
}
raxInsert(aliases, (unsigned char *)alias, strlen(alias), NULL, NULL);
}
}
static void _AST_GetWithReferences(const cypher_astnode_t *node, rax *identifiers) {
if(!node) return;
if(cypher_astnode_type(node) != CYPHER_AST_WITH) return;
assert(identifiers);
uint num_with_projections = cypher_ast_with_nprojections(node);
for(uint i = 0; i < num_with_projections; i ++) {
const cypher_astnode_t *child = cypher_ast_with_get_projection(node, i);
_AST_GetIdentifiers(child, identifiers);
}
}
// Extract identifiers / aliases from a procedure call.
static void _AST_GetProcCallAliases(const cypher_astnode_t *node, rax *identifiers) {
// CALL db.labels() yield label
// CALL db.labels() yield label as l
assert(node && identifiers);
assert(cypher_astnode_type(node) == CYPHER_AST_CALL);
uint projection_count = cypher_ast_call_nprojections(node);
for(uint i = 0; i < projection_count; i++) {
const char *identifier = NULL;
const cypher_astnode_t *proj_node = cypher_ast_call_get_projection(node, i);
const cypher_astnode_t *alias_node = cypher_ast_projection_get_alias(proj_node);
if(alias_node) {
// Alias is given: YIELD label AS l.
identifier = cypher_ast_identifier_get_name(alias_node);
} else {
// No alias, use identifier: YIELD label
const cypher_astnode_t *exp_node = cypher_ast_projection_get_expression(proj_node);
identifier = cypher_ast_identifier_get_name(exp_node);
}
assert(identifiers);
raxInsert(identifiers, (unsigned char *)identifier, strlen(identifier), NULL, NULL);
}
}
// UNWIND and WITH also form aliases, but don't need special handling for us yet.
static void _AST_GetReturnAliases(const cypher_astnode_t *node, rax *aliases) {
assert(node && aliases && cypher_astnode_type(node) == CYPHER_AST_RETURN);
uint num_return_projections = cypher_ast_return_nprojections(node);
if(num_return_projections == 0) return;
for(uint i = 0; i < num_return_projections; i ++) {
const cypher_astnode_t *child = cypher_ast_return_get_projection(node, i);
const cypher_astnode_t *alias_node = cypher_ast_projection_get_alias(child);
if(alias_node == NULL) continue;
const char *alias = cypher_ast_identifier_get_name(alias_node);
raxInsert(aliases, (unsigned char *)alias, strlen(alias), NULL, NULL);
}
}
static void _CollectIdentifiers(const cypher_astnode_t *root, rax *projections) {
if(cypher_astnode_type(root) == CYPHER_AST_IDENTIFIER) {
// Identifier found, add to triemap
const char *identifier = cypher_ast_identifier_get_name(root);
raxInsert(projections, (unsigned char *)identifier, strlen(identifier), NULL, NULL);
} else {
uint child_count = cypher_astnode_nchildren(root);
for(uint i = 0; i < child_count; i ++) {
_CollectIdentifiers(cypher_astnode_get_child(root, i), projections);
}
}
}
/* Collect all identifiers used in the RETURN clause (but not aliases defined there) */
static rax *_AST_GetReturnProjections(const cypher_astnode_t *return_clause) {
if(!return_clause) return NULL;
uint projection_count = cypher_ast_return_nprojections(return_clause);
if(projection_count == 0) return NULL;
rax *projections = raxNew();
for(uint i = 0; i < projection_count; i ++) {
const cypher_astnode_t *projection = cypher_ast_return_get_projection(return_clause, i);
_CollectIdentifiers(projection, projections);
}
return projections;
}
/* Compares a triemap of user-specified functions with the registered functions we provide. */
static AST_Validation _ValidateReferredFunctions(rax *referred_functions, bool include_aggregates) {
AST_Validation res = AST_VALID;
char funcName[32];
raxIterator it;
_prepareIterateAll(referred_functions, &it);
bool found = true;
while(raxNext(&it)) {
size_t len = it.key_len;
// No functions have a name longer than 32 characters
if(len >= 32) {
res = AST_INVALID;
break;
}
// Copy the triemap key so that we can safely add a terinator character
memcpy(funcName, it.key, len);
funcName[len] = 0;
if(AR_FuncExists(funcName)) continue;
if(Agg_FuncExists(funcName)) {
if(include_aggregates) {
continue;
} else {
// Provide a unique error for using aggregate functions from inappropriate contexts
QueryCtx_SetError("Invalid use of aggregating function '%s'", funcName);
res = AST_INVALID;
break;
}
}
// If we reach this point, the function was not found
found = false;
res = AST_INVALID;
break;
}
// If the function was not found, provide a reason if one is not set
if(res == AST_INVALID && !found) {
QueryCtx_SetError("Unknown function '%s'", funcName);
}
raxStop(&it);
return res;
}
// Recursively collect function names and perform validations on functions with STAR arguments.
static AST_Validation _VisitFunctions(const cypher_astnode_t *node, rax *func_names) {
cypher_astnode_type_t type = cypher_astnode_type(node);
if(type == CYPHER_AST_APPLY_ALL_OPERATOR) {
// Working with a function call that has * as its argument.
const cypher_astnode_t *func = cypher_ast_apply_all_operator_get_func_name(node);
const char *func_name = cypher_ast_function_name_get_value(func);
// Verify that this is a COUNT call.
if(strcasecmp(func_name, "COUNT")) {
QueryCtx_SetError("COUNT is the only function which can accept * as an argument");
return AST_INVALID;
}
// Verify that DISTINCT is not specified.
if(cypher_ast_apply_all_operator_get_distinct(node)) {
// TODO consider opening a parser error, this construction is invalid in Neo's parser.
QueryCtx_SetError("Cannot specify both DISTINCT and * in COUNT(DISTINCT *)");
return AST_INVALID;
}
// Collect the function name, which is always "count" here.
raxInsert(func_names, (unsigned char *)"count", 5, NULL, NULL);
// As Apply All operators have no children, we can return here.
return AST_VALID;
}
if(type == CYPHER_AST_APPLY_OPERATOR) {
// Collect the function name.
const cypher_astnode_t *func = cypher_ast_apply_operator_get_func_name(node);
const char *func_name = cypher_ast_function_name_get_value(func);
raxInsert(func_names, (unsigned char *)func_name, strlen(func_name), NULL, NULL);
}
uint child_count = cypher_astnode_nchildren(node);
for(uint i = 0; i < child_count; i ++) {
const cypher_astnode_t *child = cypher_astnode_get_child(node, i);
AST_Validation res = _VisitFunctions(child, func_names);
if(res != AST_VALID) return res;
}
return AST_VALID;
}
static AST_Validation _ValidateFunctionCalls(const cypher_astnode_t *node,
bool include_aggregates) {
AST_Validation res = AST_VALID;
rax *func_names = raxNew();
// Collect function names and perform in-place validations.
res = _VisitFunctions(node, func_names);
if(res != AST_VALID) goto cleanup;
// Validate all provided function names.
res = _ValidateReferredFunctions(func_names, include_aggregates);
cleanup:
raxFree(func_names);
return res;
}
static inline bool _AliasIsReturned(rax *projections, const char *identifier) {
return raxFind(projections, (unsigned char *)identifier, strlen(identifier)) != raxNotFound;
}
// If we have a multi-hop traversal (fixed or variable length), we cannot currently return that entity.
static AST_Validation _ValidateMultiHopTraversal(rax *projections, const cypher_astnode_t *edge,
const cypher_astnode_t *range) {
int start = 1;
int end = INT_MAX - 2;
const cypher_astnode_t *range_start = cypher_ast_range_get_start(range);
if(range_start) start = AST_ParseIntegerNode(range_start);
const cypher_astnode_t *range_end = cypher_ast_range_get_end(range);
if(range_end) end = AST_ParseIntegerNode(range_end);
// Validate specified range
if(start > end) {
QueryCtx_SetError("Variable length path, maximum number of hops must be greater or equal to minimum number of hops.");
return AST_INVALID;
}
bool multihop = (start > 1) || (start != end);
if(!multihop) return AST_VALID;
// Multi-hop traversals cannot (currently) be filtered on
if(cypher_ast_rel_pattern_get_properties(edge) != NULL) {
QueryCtx_SetError("RedisGraph does not currently support filters on variable-length paths.");
return AST_INVALID;
}
// Multi-hop traversals cannot be referenced
if(!projections) return AST_VALID;
// Check if relation has an alias
const cypher_astnode_t *ast_identifier = cypher_ast_rel_pattern_get_identifier(edge);
if(!ast_identifier) return AST_VALID;
// Verify that the alias is not found in the RETURN clause.
const char *identifier = cypher_ast_identifier_get_name(ast_identifier);
if(_AliasIsReturned(projections, identifier)) {
QueryCtx_SetError("RedisGraph does not support the return of variable-length traversal edges '%s'. \
Instead, use a query in the style of: 'MATCH p = (a)-[%s*]->(b) RETURN relationships(p)'.",
identifier, identifier);
return AST_INVALID;
}
return AST_VALID;
}
static AST_Validation _Validate_ReusedEdges(const cypher_astnode_t *node, rax *edge_aliases) {
uint child_count = cypher_astnode_nchildren(node);
for(uint i = 0; i < child_count; i++) {
const cypher_astnode_t *child = cypher_astnode_get_child(node, i);
cypher_astnode_type_t type = cypher_astnode_type(child);
if(type == CYPHER_AST_IDENTIFIER) {
const char *alias = cypher_ast_identifier_get_name(child);
int new1 = raxInsert(edge_aliases, (unsigned char *)alias, strlen(alias), NULL,
NULL);
if(!new1) {
char *err = NULL;
QueryCtx_SetError("Cannot use the same relationship variable '%s' for multiple patterns.", alias);
return AST_INVALID;
}
}
}
return AST_VALID;
}
static AST_Validation _ValidateRelation(rax *projections, const cypher_astnode_t *edge,
rax *edge_aliases) {
AST_Validation res = AST_VALID;
// Make sure edge alias is unique
res = _Validate_ReusedEdges(edge, edge_aliases);
if(res != AST_VALID) return res;
// If this is a multi-hop traversal, validate it
const cypher_astnode_t *range = cypher_ast_rel_pattern_get_varlength(edge);
if(range) {
res = _ValidateMultiHopTraversal(projections, edge, range);
if(res != AST_VALID) return res;
}
return res;
}
static AST_Validation _ValidatePath(const cypher_astnode_t *path, rax *projections,
rax *edge_aliases) {
AST_Validation res = AST_VALID;
uint path_len = cypher_ast_pattern_path_nelements(path);
// Check all relations on the path (every odd offset) and collect aliases.
for(uint i = 1; i < path_len; i += 2) {
const cypher_astnode_t *edge = cypher_ast_pattern_path_get_element(path, i);
res = _ValidateRelation(projections, edge, edge_aliases);
if(res != AST_VALID) return res;
}
return res;
}
static AST_Validation _ValidatePattern(rax *projections, const cypher_astnode_t *pattern,
rax *edge_aliases) {
AST_Validation res = AST_VALID;
uint path_count = cypher_ast_pattern_npaths(pattern);
for(uint i = 0; i < path_count; i ++) {
res = _ValidatePath(cypher_ast_pattern_get_path(pattern, i), projections, edge_aliases);
if(res != AST_VALID) break;
}
return res;
}
// Validate the property maps used in node/edge patterns in MATCH, and CREATE clauses
static AST_Validation _ValidateInlinedProperties(const cypher_astnode_t *props) {
if(cypher_astnode_type(props) != CYPHER_AST_MAP) {
// Emit an error if the properties are not presented as a map, as in:
// MATCH (p {invalid_property_construction}) RETURN p
QueryCtx_SetError("Encountered unhandled type in inlined properties.");
return AST_INVALID;
}
return AST_VALID;
}
static AST_Validation _ValidateInlinedPropertiesOnPath(const cypher_astnode_t *path) {
uint path_len = cypher_ast_pattern_path_nelements(path);
// Check all nodes on path
for(uint i = 0; i < path_len; i += 2) {
const cypher_astnode_t *ast_identifier = NULL;
const cypher_astnode_t *node = cypher_ast_pattern_path_get_element(path, i);
const cypher_astnode_t *props = cypher_ast_node_pattern_get_properties(node);
if(props && (_ValidateInlinedProperties(props) != AST_VALID)) return AST_INVALID;
}
// Check all edges on path
for(uint i = 1; i < path_len; i += 2) {
const cypher_astnode_t *ast_identifier = NULL;
const cypher_astnode_t *edge = cypher_ast_pattern_path_get_element(path, i);
const cypher_astnode_t *props = cypher_ast_rel_pattern_get_properties(edge);
if(props && (_ValidateInlinedProperties(props) != AST_VALID)) return AST_INVALID;
}
return AST_VALID;
}
static AST_Validation _Validate_MATCH_Clause_Filters(const cypher_astnode_t *clause) {
const cypher_astnode_t *pattern = cypher_ast_match_get_pattern(clause);
uint path_count = cypher_ast_pattern_npaths(pattern);
for(uint i = 0; i < path_count; i ++) {
const cypher_astnode_t *path = cypher_ast_pattern_get_path(pattern, i);
if(_ValidateInlinedPropertiesOnPath(path) != AST_VALID) return AST_INVALID;
}
return AST_VALID;
}
static AST_Validation _Validate_CALL_Clauses(const AST *ast) {
/* Make sure procedure calls are valid:
* 1. procedure exists
* 2. number of arguments to procedure is as expected
* 3. yield refers to procedure output */
const cypher_astnode_t **call_clauses = AST_GetClauses(ast, CYPHER_AST_CALL);
if(call_clauses == NULL) return AST_VALID;
AST_Validation res = AST_VALID;
ProcedureCtx *proc = NULL;
rax *identifiers = raxNew();
uint call_count = array_len(call_clauses);
for(uint i = 0; i < call_count; i ++) {
const cypher_astnode_t *call_clause = call_clauses[i];
// Make sure procedure exists.
const char *proc_name = cypher_ast_proc_name_get_value(cypher_ast_call_get_proc_name(call_clause));
proc = Proc_Get(proc_name);
if(proc == NULL) {
QueryCtx_SetError("Procedure `%s` is not registered", proc_name);
res = AST_INVALID;
goto cleanup;
}
// Validate num of arguments.
if(proc->argc != PROCEDURE_VARIABLE_ARG_COUNT) {
unsigned int given_arg_count = cypher_ast_call_narguments(call_clause);
if(Procedure_Argc(proc) != given_arg_count) {
QueryCtx_SetError("Procedure `%s` requires %d arguments, got %d", proc_name, proc->argc,
given_arg_count);
res = AST_INVALID;
goto cleanup;
}
}
// Validate projections.
uint proj_count = cypher_ast_call_nprojections(call_clause);
if(proj_count > 0) {
// Collect call projections.
for(uint j = 0; j < proj_count; j++) {
const cypher_astnode_t *proj = cypher_ast_call_get_projection(call_clause, j);
const cypher_astnode_t *ast_exp = cypher_ast_projection_get_expression(proj);
assert(cypher_astnode_type(ast_exp) == CYPHER_AST_IDENTIFIER);
const char *identifier = cypher_ast_identifier_get_name(ast_exp);
// Make sure each yield output is mentioned only once.
if(!raxInsert(identifiers, (unsigned char *)identifier, strlen(identifier), NULL,
NULL)) {
QueryCtx_SetError("Variable `%s` already declared", identifier);
res = AST_INVALID;
goto cleanup;
}
}
// Make sure procedure is aware of each output.
char output[256];
raxIterator it;
_prepareIterateAll(identifiers, &it);
while(raxNext(&it)) {
size_t len = it.key_len;
unsigned char *identifier = it.key;
if(len >= 256) {
QueryCtx_SetError("Output name `%s` too long", identifier);
res = AST_INVALID;
goto cleanup;
}
memcpy(output, identifier, len);
output[len] = 0;
if(!Procedure_ContainsOutput(proc, output)) {
raxStop(&it);
QueryCtx_SetError("Procedure `%s` does not yield output `%s`", proc_name, output);
res = AST_INVALID;
goto cleanup;
}
}
raxStop(&it);
raxFree(identifiers);
identifiers = NULL;
}
Proc_Free(proc);
proc = NULL;
}
cleanup:
if(proc) Proc_Free(proc);
array_free(call_clauses);
if(identifiers) raxFree(identifiers);
return res;
}
static AST_Validation _ValidateNodeAlias(const cypher_astnode_t *node, rax *edge_aliases) {
const cypher_astnode_t *ast_alias = cypher_ast_node_pattern_get_identifier(node);
if(ast_alias == NULL) return AST_VALID;
// Verify that the node's alias is not in the map of edge aliases.
const char *alias = cypher_ast_identifier_get_name(ast_alias);
if(raxFind(edge_aliases, (unsigned char *)alias, strlen(alias)) != raxNotFound) {
QueryCtx_SetError("The alias '%s' was specified for both a node and a relationship.", alias);
return AST_INVALID;
}
return AST_VALID;
}
static AST_Validation _ValidateReusedAliases(rax *edge_aliases, const cypher_astnode_t *pattern) {
AST_Validation res = AST_VALID;
uint path_count = cypher_ast_pattern_npaths(pattern);
for(uint i = 0; i < path_count; i ++) {
const cypher_astnode_t *path = cypher_ast_pattern_get_path(pattern, i);
uint path_len = cypher_ast_pattern_path_nelements(path);
for(uint j = 0; j < path_len; j += 2) {
const cypher_astnode_t *node = cypher_ast_pattern_path_get_element(path, j);
res = _ValidateNodeAlias(node, edge_aliases);
if(res != AST_VALID) return res;
}
}
return res;
}
static AST_Validation _Validate_MATCH_Clauses(const AST *ast) {
// Check to see if all mentioned inlined, outlined functions exists.
// Inlined functions appear within entity definition ({a:v})
// Outlined functions appear within the WHERE clause.
// libcypher-parser doesn't have a WHERE node, all of the filters
// are specified within the MATCH node sub-tree.
const cypher_astnode_t **match_clauses = AST_GetClauses(ast, CYPHER_AST_MATCH);
if(match_clauses == NULL) return AST_VALID;
rax *edge_aliases = raxNew();
rax *reused_entities = raxNew();
AST_Validation res;
const cypher_astnode_t *return_clause = AST_GetClause(ast, CYPHER_AST_RETURN);
rax *projections = _AST_GetReturnProjections(return_clause);
uint match_count = array_len(match_clauses);
for(uint i = 0; i < match_count; i ++) {
const cypher_astnode_t *match_clause = match_clauses[i];
// Validate the pattern described by the MATCH clause
res = _ValidatePattern(projections, cypher_ast_match_get_pattern(match_clause), edge_aliases);
if(res == AST_INVALID) goto cleanup;
// Validate that inlined filters do not use parameters
res = _Validate_MATCH_Clause_Filters(match_clause);
if(res == AST_INVALID) goto cleanup;
// Validate all function references in clause. Aggregate calls cannot be made in MATCH
// clauses or their WHERE predicates.
bool include_aggregates = false;
res = _ValidateFunctionCalls(match_clause, include_aggregates);
if(res == AST_INVALID) goto cleanup;
}
// Verify that no relation alias is also used to denote a node
for(uint i = 0; i < match_count; i ++) {
const cypher_astnode_t *match_clause = match_clauses[i];
res = _ValidateReusedAliases(edge_aliases, cypher_ast_match_get_pattern(match_clause));
if(res == AST_INVALID) goto cleanup;
}
cleanup:
if(projections) raxFree(projections);
raxFree(edge_aliases);
raxFree(reused_entities);
array_free(match_clauses);
return res;
}
static AST_Validation _Validate_WITH_Clauses(const AST *ast) {
// Verify that all functions used in the WITH clause and (if present) its WHERE predicate
// are defined and used validly.
// An AST segment has at most 1 WITH clause.
const cypher_astnode_t *with_clause = AST_GetClause(ast, CYPHER_AST_WITH);
if(with_clause == NULL) return AST_VALID;
// Verify that each WITH projection either is aliased or is itself an identifier.
uint projection_count = cypher_ast_with_nprojections(with_clause);
for(uint i = 0; i < projection_count; i ++) {
const cypher_astnode_t *proj = cypher_ast_with_get_projection(with_clause, i);
if(!cypher_ast_projection_get_alias(proj) &&
cypher_astnode_type(cypher_ast_projection_get_expression(proj)) != CYPHER_AST_IDENTIFIER) {
QueryCtx_SetError("WITH clause projections must be aliased");
return AST_INVALID;
}
}
// Verify that functions invoked by the WITH clause are valid.
return _ValidateFunctionCalls(with_clause, true);
}
// Verify that MERGE doesn't redeclare bound relations and that one reltype is specified for unbound relations.
static AST_Validation _ValidateMergeRelation(const cypher_astnode_t *entity, rax *defined_aliases) {
const cypher_astnode_t *identifier = cypher_ast_rel_pattern_get_identifier(entity);
const char *alias = NULL;
if(identifier) {
alias = cypher_ast_identifier_get_name(identifier);
// Verify that we're not redeclaring a bound variable.
if(raxFind(defined_aliases, (unsigned char *)alias, strlen(alias)) != raxNotFound) {
QueryCtx_SetError("The bound variable %s' can't be redeclared in a MERGE clause", alias);
return AST_INVALID;
}
}
// Exactly one reltype should be specified for the introduced edge.
uint reltype_count = cypher_ast_rel_pattern_nreltypes(entity);
if(reltype_count != 1) {
QueryCtx_SetError("Exactly one relationship type must be specified for each relation in a MERGE pattern.");
return AST_INVALID;
}
// We don't need to validate the MERGE edge's direction, as an undirected edge in MERGE
// should cause a single outgoing edge to be created.
return AST_VALID;
}
// Verify that MERGE doesn't redeclare bound nodes.
static AST_Validation _ValidateMergeNode(const cypher_astnode_t *entity, rax *defined_aliases) {
if(raxSize(defined_aliases) == 0) return AST_VALID;
const cypher_astnode_t *identifier = cypher_ast_node_pattern_get_identifier(entity);
if(identifier == NULL) return AST_VALID;
const char *alias = cypher_ast_identifier_get_name(identifier);
if(raxFind(defined_aliases, (unsigned char *)alias, strlen(alias)) == raxNotFound) {
// If the entity is unaliased or not previously bound, it cannot be redeclared.
return AST_VALID;
}
// If the entity is already bound, the MERGE pattern should not introduce labels or properties.
if((cypher_ast_node_pattern_nlabels(entity) > 0) ||
cypher_ast_node_pattern_get_properties(entity)) {
QueryCtx_SetError("The bound node '%s' can't be redeclared in a MERGE clause", alias);
return AST_INVALID;
}
return AST_VALID;
}
static AST_Validation _Validate_MERGE_Clauses(const AST *ast) {
AST_Validation res = AST_VALID;
uint *merge_clause_indices = AST_GetClauseIndices(ast, CYPHER_AST_MERGE);
uint merge_count = array_len(merge_clause_indices);
rax *defined_aliases = NULL;
if(merge_count == 0) goto cleanup;
defined_aliases = raxNew();
uint start_offset = 0;
for(uint i = 0; i < merge_count; i ++) {
uint clause_idx = merge_clause_indices[i];
// Collect all entities that are bound before this MERGE clause.
for(uint j = start_offset; j < clause_idx; j ++) {
const cypher_astnode_t *clause = cypher_ast_query_get_clause(ast->root, j);
_AST_GetDefinedIdentifiers(clause, defined_aliases);
}
start_offset = clause_idx;
const cypher_astnode_t *merge_clause = cypher_ast_query_get_clause(ast->root, clause_idx);
const cypher_astnode_t *path = cypher_ast_merge_get_pattern_path(merge_clause);
uint nelems = cypher_ast_pattern_path_nelements(path);
for(uint j = 0; j < nelems; j ++) {
const cypher_astnode_t *entity = cypher_ast_pattern_path_get_element(path, j);
// Odd offsets correspond to edges, even offsets correspond to nodes.
res = (j % 2) ? _ValidateMergeRelation(entity, defined_aliases)
: _ValidateMergeNode(entity, defined_aliases);
if(res != AST_VALID) goto cleanup;
}
// Verify that any filters on the path refer to constants or resolved identifiers.
res = _ValidateInlinedPropertiesOnPath(path);
if(res != AST_VALID) goto cleanup;
}
cleanup:
array_free(merge_clause_indices);
if(defined_aliases) raxFree(defined_aliases);
return res;
}
// Validate each entity referenced in the CREATE clause.
static AST_Validation _Validate_CREATE_Entities(const cypher_astnode_t *clause,
rax *defined_aliases) {
const cypher_astnode_t *pattern = cypher_ast_create_get_pattern(clause);
// Verify that functions invoked in the CREATE pattern are valid.
if(_ValidateFunctionCalls(pattern, false) != AST_VALID) return AST_INVALID;
uint path_count = cypher_ast_pattern_npaths(pattern);
for(uint i = 0; i < path_count; i ++) {
const cypher_astnode_t *path = cypher_ast_pattern_get_path(pattern, i);
// Validate that inlined properties are valid.
if(_ValidateInlinedPropertiesOnPath(path) != AST_VALID) return AST_INVALID;
uint nelems = cypher_ast_pattern_path_nelements(path);
/* Visit every relationship (every odd offset) on the path to validate its alias and structure.
* TODO There should also be a syntax error for redeclaring nodes, as in:
* MATCH (a) CREATE (a)
* But this is a no-op query, and we don't have the logic to differentiate this from a valid query like
* MATCH (a) CREATE (a)-[:E]->(:B) */
for(uint j = 1; j < nelems; j += 2) {
const cypher_astnode_t *rel = cypher_ast_pattern_path_get_element(path, j);
const cypher_astnode_t *identifier = cypher_ast_rel_pattern_get_identifier(rel);
// Validate that no relation aliases are previously bound.
if(identifier) {
const char *alias = cypher_ast_identifier_get_name(identifier);
if(raxFind(defined_aliases, (unsigned char *)alias, strlen(alias)) != raxNotFound) {
QueryCtx_SetError("The bound variable %s' can't be redeclared in a CREATE clause", alias);
return AST_INVALID;
}
}
// Validate that each relation has exactly one type.
uint reltype_count = cypher_ast_rel_pattern_nreltypes(rel);
if(reltype_count != 1) {
QueryCtx_SetError("Exactly one relationship type must be specified for CREATE");
return AST_INVALID;
}
// Validate that each relation being created is directed.
if(cypher_ast_rel_pattern_get_direction(rel) == CYPHER_REL_BIDIRECTIONAL) {
QueryCtx_SetError("Only directed relationships are supported in CREATE");
return AST_INVALID;
}
}
}
return AST_VALID;
}
static AST_Validation _Validate_CREATE_Clauses(const AST *ast) {
AST_Validation res = AST_VALID;
uint *create_clause_indices = AST_GetClauseIndices(ast, CYPHER_AST_CREATE);
uint clause_count = array_len(create_clause_indices);
rax *defined_aliases = NULL;
if(clause_count == 0) goto cleanup;
defined_aliases = raxNew();
uint start_offset = 0;
for(uint i = 0; i < clause_count; i ++) {
uint clause_idx = create_clause_indices[i];
// Collect all entities that are bound before this CREATE clause.
for(uint j = start_offset; j < clause_idx; j ++) {
const cypher_astnode_t *prev_clause = cypher_ast_query_get_clause(ast->root, i);
_AST_GetDefinedIdentifiers(prev_clause, defined_aliases);
}
start_offset = clause_idx;
const cypher_astnode_t *clause = cypher_ast_query_get_clause(ast->root, clause_idx);
res = _Validate_CREATE_Entities(clause, defined_aliases);
if(res == AST_INVALID) goto cleanup;
}
/* Since we combine all our CREATE clauses in a segment into one operation,
* make sure no data-modifying clauses can separate them. TCK example:
* CREATE (a:A), (b:B) MERGE (a)-[:KNOWS]->(b) CREATE (b)-[:KNOWS]->(c:C) RETURN count(*)
*/
for(uint i = create_clause_indices[0] + 1; i < create_clause_indices[clause_count - 1]; i ++) {
const cypher_astnode_t *clause = cypher_ast_query_get_clause(ast->root, i);
if(cypher_astnode_type(clause) == CYPHER_AST_MERGE) {
QueryCtx_SetError("RedisGraph does not support queries of the form CREATE...MERGE...CREATE without a separating WITH clause.");
res = AST_INVALID;
goto cleanup;
}
}
cleanup:
array_free(create_clause_indices);
if(defined_aliases) raxFree(defined_aliases);
return res;
}
static AST_Validation _Validate_DELETE_Clauses(const AST *ast) {
const cypher_astnode_t *delete_clause = AST_GetClause(ast, CYPHER_AST_DELETE);
if(!delete_clause) return AST_VALID;
// TODO: Validated that the deleted entities are indeed matched or projected.
return AST_VALID;
}
static AST_Validation _Validate_RETURN_Clause(const AST *ast) {
const cypher_astnode_t *return_clause = AST_GetClause(ast, CYPHER_AST_RETURN);
if(!return_clause) return AST_VALID;
// Validate all user-specified functions in RETURN clause.
bool include_aggregates = true;
AST_Validation res = _ValidateFunctionCalls(return_clause, include_aggregates);
return res;
}
static AST_Validation _Validate_UNWIND_Clauses(const AST *ast) {
const cypher_astnode_t **unwind_clauses = AST_GetClauses(ast, CYPHER_AST_UNWIND);
if(!unwind_clauses) return AST_VALID;
AST_Validation res = AST_VALID;
uint clause_count = array_len(unwind_clauses);
for(uint i = 0; i < clause_count; i++) {
const cypher_astnode_t *expression = cypher_ast_unwind_get_expression(unwind_clauses[i]);
// Verify that all elements of the UNWIND collection are supported by RedisGraph
uint child_count = cypher_astnode_nchildren(expression);
for(uint j = 0; j < child_count; j ++) {
res = CypherWhitelist_ValidateQuery(cypher_astnode_get_child(expression, j));
if(res != AST_VALID) goto cleanup;
}
// Verify that UNWIND doesn't call non-existent or unsupported functions.
res = _ValidateFunctionCalls(expression, true);
if(res != AST_VALID) goto cleanup;
}
cleanup:
array_free(unwind_clauses);
return res;
}
// LIMIT and SKIP are not independent clauses, but modifiers that can be applied to WITH or RETURN clauses
static AST_Validation _Validate_LIMIT_SKIP_Modifiers(const AST *ast) {
// Handle modifiers on the RETURN clause
const cypher_astnode_t *return_clause = AST_GetClause(ast, CYPHER_AST_RETURN);
// Skip check if the RETURN clause does not specify a limit
if(return_clause) {
// Handle LIMIT modifier
const cypher_astnode_t *limit = cypher_ast_return_get_limit(return_clause);
if(limit) {
// Handle non-integer or non parameter types specified as LIMIT value
// The value validation of integer node or parameter node is done in run time evaluation.
if(cypher_astnode_type(limit) != CYPHER_AST_INTEGER &&
cypher_astnode_type(limit) != CYPHER_AST_PARAMETER) {
QueryCtx_SetError("LIMIT specified value of invalid type, must be a positive integer");
return AST_INVALID;
}
}
// Handle SKIP modifier
const cypher_astnode_t *skip = cypher_ast_return_get_skip(return_clause);
if(skip) {
// Handle non-integer or non parameter types specified as skip value
// The value validation of integer node or parameter node is done in run time evaluation.
if(cypher_astnode_type(skip) != CYPHER_AST_INTEGER &&
cypher_astnode_type(skip) != CYPHER_AST_PARAMETER) {
QueryCtx_SetError("SKIP specified value of invalid type, must be a positive integer");
return AST_INVALID;
}
}
}
// Handle LIMIT modifiers on all WITH clauses
const cypher_astnode_t **with_clauses = AST_GetClauses(ast, CYPHER_AST_WITH);
if(!with_clauses) return AST_VALID;
AST_Validation res = AST_VALID;
uint with_count = array_len(with_clauses);
for(uint i = 0; i < with_count; i++) {
const cypher_astnode_t *with_clause = with_clauses[i];
// Handle LIMIT modifier
const cypher_astnode_t *limit = cypher_ast_with_get_limit(with_clause);
if(limit) {
// Handle non-integer or non parameter types specified as LIMIT value
// The value validation of integer node or parameter node is done in run time evaluation.
if(cypher_astnode_type(limit) != CYPHER_AST_INTEGER &&
cypher_astnode_type(limit) != CYPHER_AST_PARAMETER) {
QueryCtx_SetError("LIMIT specified value of invalid type, must be a positive integer");
return AST_INVALID;
}
}
// Handle SKIP modifier
const cypher_astnode_t *skip = cypher_ast_with_get_skip(with_clause);
if(skip) {
// Handle non-integer or non parameter types specified as skip value
// The value validation of integer node or parameter node is done in run time evaluation.
if(cypher_astnode_type(skip) != CYPHER_AST_INTEGER &&
cypher_astnode_type(skip) != CYPHER_AST_PARAMETER) {
QueryCtx_SetError("SKIP specified value of invalid type, must be a positive integer");
return AST_INVALID;
}
}
}
array_free(with_clauses);
return res;
}
// A query must end in a RETURN clause, a procedure, or an updating clause
// (CREATE, MERGE, DELETE, SET, or REMOVE once supported)
static AST_Validation _ValidateQueryTermination(const AST *ast) {
uint clause_count = cypher_ast_query_nclauses(ast->root);
const cypher_astnode_t *last_clause = cypher_ast_query_get_clause(ast->root, clause_count - 1);
cypher_astnode_type_t type = cypher_astnode_type(last_clause);
if(type != CYPHER_AST_RETURN &&
type != CYPHER_AST_CREATE &&
type != CYPHER_AST_MERGE &&
type != CYPHER_AST_DELETE &&
type != CYPHER_AST_SET &&
type != CYPHER_AST_CALL
) {
QueryCtx_SetError("Query cannot conclude with %s (must be RETURN or an update clause)",
cypher_astnode_typestr(type));
return AST_INVALID;
}
return AST_VALID;
}
static void _AST_RegisterCallOutputs(const cypher_astnode_t *call_clause, rax *identifiers) {
const char *proc_name = cypher_ast_proc_name_get_value(cypher_ast_call_get_proc_name(call_clause));
ProcedureCtx *proc = Proc_Get(proc_name);
assert(proc);
unsigned int output_count = array_len(proc->output);
for(uint i = 0; i < output_count; i++) {
const char *name = Procedure_GetOutput(proc, i);
raxInsert(identifiers, (unsigned char *)name, strlen(name), NULL, NULL);
}
}
// Perform validations not constrained to a specific scope
static AST_Validation _ValidateQuerySequence(const AST *ast) {
// Validate the final clause
if(_ValidateQueryTermination(ast) != AST_VALID) return AST_INVALID;
uint clause_count = cypher_ast_query_nclauses(ast->root);
// The query cannot begin with a "WITH/RETURN *" projection.
const cypher_astnode_t *start_clause = cypher_ast_query_get_clause(ast->root, 0);
if(cypher_astnode_type(start_clause) == CYPHER_AST_WITH &&
cypher_ast_with_has_include_existing(start_clause)) {
QueryCtx_SetError("Query cannot begin with 'WITH *'.");
return AST_INVALID;
}
if(cypher_astnode_type(start_clause) == CYPHER_AST_RETURN &&
cypher_ast_return_has_include_existing(start_clause)) {
QueryCtx_SetError("Query cannot begin with 'RETURN *'.");
return AST_INVALID;
}
return AST_VALID;
}
/* In any given query scope, reading clauses (MATCH, UNWIND, and InQueryCall)
* cannot follow updating clauses (CREATE, MERGE, DELETE, SET, REMOVE).
* https://s3.amazonaws.com/artifacts.opencypher.org/railroad/SinglePartQuery.html
* Additionally, a MATCH clause cannot follow an OPTIONAL MATCH clause. */
static AST_Validation _ValidateClauseOrder(const AST *ast) {
uint clause_count = cypher_ast_query_nclauses(ast->root);
bool encountered_optional_match = false;
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