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authorJunio C Hamano <gitster@pobox.com>2012-09-13 14:21:44 -0700
committerJunio C Hamano <gitster@pobox.com>2012-09-14 10:10:35 -0700
commit17bf35a3c7b46df7131681bcc5bee5f12e1caec4 (patch)
tree26c22e3e4dce563d22a840d6a9b2f144a2335b57 /grep.c
parent785ee4960c3d334cbc2b17ab74d2cebdf1b4db64 (diff)
downloadgit-17bf35a3c7b46df7131681bcc5bee5f12e1caec4.tar.gz
grep: teach --debug option to dump the parse tree
Our "grep" allows complex boolean expressions to be formed to match each individual line with operators like --and, '(', ')' and --not. Introduce the "--debug" option to show the parse tree to help people who want to debug and enhance it. Also "log" learns "--grep-debug" option to do the same. The command line parser to the log family is a lot more limited than the general "git grep" parser, but it has special handling for header matching (e.g. "--author"), and a parse tree is valuable when working on it. Note that "--all-match" is *not* any individual node in the parse tree. It is an instruction to the evaluator to check all the nodes in the top-level backbone have matched and reject a document as non-matching otherwise. Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'grep.c')
-rw-r--r--grep.c92
1 files changed, 90 insertions, 2 deletions
diff --git a/grep.c b/grep.c
index 04e3ec6c6e..be15c4753d 100644
--- a/grep.c
+++ b/grep.c
@@ -332,6 +332,87 @@ static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
return compile_pattern_or(list);
}
+static void indent(int in)
+{
+ while (in-- > 0)
+ fputc(' ', stderr);
+}
+
+static void dump_grep_pat(struct grep_pat *p)
+{
+ switch (p->token) {
+ case GREP_AND: fprintf(stderr, "*and*"); break;
+ case GREP_OPEN_PAREN: fprintf(stderr, "*(*"); break;
+ case GREP_CLOSE_PAREN: fprintf(stderr, "*)*"); break;
+ case GREP_NOT: fprintf(stderr, "*not*"); break;
+ case GREP_OR: fprintf(stderr, "*or*"); break;
+
+ case GREP_PATTERN: fprintf(stderr, "pattern"); break;
+ case GREP_PATTERN_HEAD: fprintf(stderr, "pattern_head"); break;
+ case GREP_PATTERN_BODY: fprintf(stderr, "pattern_body"); break;
+ }
+
+ switch (p->token) {
+ default: break;
+ case GREP_PATTERN_HEAD:
+ fprintf(stderr, "<head %d>", p->field); break;
+ case GREP_PATTERN_BODY:
+ fprintf(stderr, "<body>"); break;
+ }
+ switch (p->token) {
+ default: break;
+ case GREP_PATTERN_HEAD:
+ case GREP_PATTERN_BODY:
+ case GREP_PATTERN:
+ fprintf(stderr, "%.*s", (int)p->patternlen, p->pattern);
+ break;
+ }
+ fputc('\n', stderr);
+}
+
+static void dump_grep_expression_1(struct grep_expr *x, int in)
+{
+ indent(in);
+ switch (x->node) {
+ case GREP_NODE_TRUE:
+ fprintf(stderr, "true\n");
+ break;
+ case GREP_NODE_ATOM:
+ dump_grep_pat(x->u.atom);
+ break;
+ case GREP_NODE_NOT:
+ fprintf(stderr, "(not\n");
+ dump_grep_expression_1(x->u.unary, in+1);
+ indent(in);
+ fprintf(stderr, ")\n");
+ break;
+ case GREP_NODE_AND:
+ fprintf(stderr, "(and\n");
+ dump_grep_expression_1(x->u.binary.left, in+1);
+ dump_grep_expression_1(x->u.binary.right, in+1);
+ indent(in);
+ fprintf(stderr, ")\n");
+ break;
+ case GREP_NODE_OR:
+ fprintf(stderr, "(or\n");
+ dump_grep_expression_1(x->u.binary.left, in+1);
+ dump_grep_expression_1(x->u.binary.right, in+1);
+ indent(in);
+ fprintf(stderr, ")\n");
+ break;
+ }
+}
+
+void dump_grep_expression(struct grep_opt *opt)
+{
+ struct grep_expr *x = opt->pattern_expression;
+
+ if (opt->all_match)
+ fprintf(stderr, "[all-match]\n");
+ dump_grep_expression_1(x, 0);
+ fflush(NULL);
+}
+
static struct grep_expr *grep_true_expr(void)
{
struct grep_expr *z = xcalloc(1, sizeof(*z));
@@ -395,7 +476,7 @@ static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
return header_expr;
}
-void compile_grep_patterns(struct grep_opt *opt)
+static void compile_grep_patterns_real(struct grep_opt *opt)
{
struct grep_pat *p;
struct grep_expr *header_expr = prep_header_patterns(opt);
@@ -415,7 +496,7 @@ void compile_grep_patterns(struct grep_opt *opt)
if (opt->all_match || header_expr)
opt->extended = 1;
- else if (!opt->extended)
+ else if (!opt->extended && !opt->debug)
return;
p = opt->pattern_list;
@@ -435,6 +516,13 @@ void compile_grep_patterns(struct grep_opt *opt)
opt->all_match = 1;
}
+void compile_grep_patterns(struct grep_opt *opt)
+{
+ compile_grep_patterns_real(opt);
+ if (opt->debug)
+ dump_grep_expression(opt);
+}
+
static void free_pattern_expr(struct grep_expr *x)
{
switch (x->node) {