[rewriter] capture rewriter command output

Also, SQL statements should populate variables.

Related to #1218

src/lnav_commands.cc

@@ -1269,14 +1269,14 @@ json_write_row(yajl_gen handle,
                     default:
                         obj_map.gen(anonymize
                                         ? ta.next(string_fragment::from_c_str(
-                                            dls.dls_rows[row][col]))
+                                              dls.dls_rows[row][col]))
                                         : dls.dls_rows[row][col]);
                         break;
                 }
                 break;
             default:
                 obj_map.gen(anonymize ? ta.next(string_fragment::from_c_str(
-                                dls.dls_rows[row][col]))
+                                            dls.dls_rows[row][col]))
                                       : dls.dls_rows[row][col]);
                 break;
         }

src/log_format.cc

@@ -1761,11 +1761,35 @@ external_log_format::rewrite(exec_context& ec,
             vd_iter->second->vd_rewrite_src_name, 1, vd.vd_rewriter);
         std::string field_value;
 
-        auto exec_res = execute_any(ec, vd.vd_rewriter);
-        if (exec_res.isOk()) {
-            field_value = exec_res.unwrap();
-        } else {
-            field_value = exec_res.unwrapErr().to_attr_line().get_string();
+        auto_mem<FILE> tmpout(fclose);
+
+        tmpout = std::tmpfile();
+        if (!tmpout) {
+            log_error("unable to create temporary file");
+            return;
+        }
+        fcntl(fileno(tmpout), F_SETFD, FD_CLOEXEC);
+        auto fd_copy = auto_fd::dup_of(fileno(tmpout));
+        fd_copy.close_on_exec();
+        auto ec_out = std::make_pair(tmpout.release(), fclose);
+        {
+            exec_context::output_guard og(ec, "tmp", ec_out);
+
+            auto exec_res = execute_any(ec, vd.vd_rewriter);
+            if (exec_res.isOk()) {
+                field_value = exec_res.unwrap();
+            } else {
+                field_value = exec_res.unwrapErr().to_attr_line().get_string();
+            }
+        }
+        struct stat st;
+        fstat(fd_copy.get(), &st);
+        if (st.st_size > 0) {
+            auto buf = auto_buffer::alloc(st.st_size);
+
+            buf.resize(st.st_size);
+            pread(fd_copy.get(), buf.in(), st.st_size, 0);
+            field_value = buf.to_string();
         }
         value_out.erase(iter->lv_origin.lr_start, iter->lv_origin.length());
 

src/logfile_sub_source.cc

@@ -63,7 +63,7 @@ pretty_sql_callback(exec_context& ec, sqlite3_stmt* stmt)
         return 0;
     }
 
-    int ncols = sqlite3_column_count(stmt);
+    const auto ncols = sqlite3_column_count(stmt);
 
     for (int lpc = 0; lpc < ncols; lpc++) {
         if (!ec.ec_accumulator->empty()) {
@@ -78,6 +78,44 @@ pretty_sql_callback(exec_context& ec, sqlite3_stmt* stmt)
         ec.ec_accumulator->append(res);
     }
 
+    for (int lpc = 0; lpc < ncols; lpc++) {
+        const auto* colname = sqlite3_column_name(stmt, lpc);
+        auto* raw_value = sqlite3_column_value(stmt, lpc);
+        auto value_type = sqlite3_value_type(raw_value);
+        scoped_value_t value;
+
+        switch (value_type) {
+            case SQLITE_INTEGER:
+                value = (int64_t) sqlite3_value_int64(raw_value);
+                break;
+            case SQLITE_FLOAT:
+                value = sqlite3_value_double(raw_value);
+                break;
+            case SQLITE_NULL:
+                value = null_value_t{};
+                break;
+            default:
+                value = string_fragment::from_bytes(
+                    sqlite3_value_text(raw_value),
+                    sqlite3_value_bytes(raw_value));
+                break;
+        }
+        if (!ec.ec_local_vars.empty() && !ec.ec_dry_run) {
+            if (sql_ident_needs_quote(colname)) {
+                continue;
+            }
+            auto& vars = ec.ec_local_vars.top();
+
+            if (vars.find(colname) != vars.end()) {
+                continue;
+            }
+
+            if (value.is<string_fragment>()) {
+                value = value.get<string_fragment>().to_string();
+            }
+            vars[colname] = value;
+        }
+    }
     return 0;
 }
 

test/formats/jsontest/rewrite-user.lnav

@@ -1,2 +1,3 @@
 
-;SELECT 'mailto:' || :user
+;SELECT 'mailto:' || :user AS mt
+:echo $mt