add logging struct with -u json options flag, log tiling progress [#13]

Makefile

@@ -47,7 +47,7 @@ C = $(wildcard *.c) $(wildcard *.cpp)
 INCLUDES = -I/usr/local/include -I.
 LIBS = -L/usr/local/lib
 
-tippecanoe: geojson.o jsonpull/jsonpull.o tile.o pool.o mbtiles.o geometry.o projection.o memfile.o mvt.o serial.o main.o text.o dirtiles.o plugin.o read_json.o write_json.o geobuf.o flatgeobuf.o evaluator.o geocsv.o csv.o geojson-loop.o
+tippecanoe: geojson.o jsonpull/jsonpull.o tile.o pool.o mbtiles.o geometry.o projection.o memfile.o mvt.o serial.o main.o text.o dirtiles.o plugin.o read_json.o write_json.o geobuf.o flatgeobuf.o evaluator.o geocsv.o csv.o geojson-loop.o json_logger.o
 	$(CXX) $(PG) $(LIBS) $(FINAL_FLAGS) $(CXXFLAGS) -o $@ $^ $(LDFLAGS) -lm -lz -lsqlite3 -lpthread
 
 tippecanoe-enumerate: enumerate.o

README.md

@@ -529,6 +529,7 @@ the same layer, enclose them in an `all` expression so they will all be evaluate
  * `-q` or `--quiet`: Work quietly instead of reporting progress or warning messages
  * `-Q` or `--no-progress-indicator`: Don't report progress, but still give warnings
  * `-U` _seconds_ or `--progress-interval=`_seconds_: Don't report progress more often than the specified number of _seconds_.
+ * `-u` or `--json-progress`: like `-quiet` but logs progress as a JSON object. Use in combination with `-U`.
  * `-v` or `--version`: Report Tippecanoe's version number
 
 ### Filters

json_logger.cpp

@@ -0,0 +1,8 @@
+#include <stdarg.h>
+#include <fstream>
+
+#include "json_logger.hpp"
+
+void json_logger::progress_tile(double progress) {
+  fprintf(stderr,"{\"progress\":%3.1f}\n",progress);
+}

json_logger.hpp

@@ -0,0 +1,13 @@
+#include <iostream>
+
+#ifndef LOGGING_HPP
+#define LOGGING_HPP
+
+
+struct json_logger {
+   bool json_enabled = false;
+
+   void progress_tile(double progress);
+};
+
+#endif

main.cpp

@@ -69,6 +69,7 @@ static int min_detail = 7;
 
 int quiet = 0;
 int quiet_progress = 0;
+json_logger logger;
 double progress_interval = 0;
 std::atomic<double> last_progress(0);
 int geometry_scale = 0;
@@ -2690,6 +2691,7 @@ int main(int argc, char **argv) {
 		{"quiet", no_argument, 0, 'q'},
 		{"no-progress-indicator", no_argument, 0, 'Q'},
 		{"progress-interval", required_argument, 0, 'U'},
+		{"json-progress", no_argument, 0, 'u'},
 		{"version", no_argument, 0, 'v'},
 
 		{"", 0, 0, 0},
@@ -3003,6 +3005,11 @@ int main(int argc, char **argv) {
 			quiet_progress = 1;
 			break;
 
+		case 'u':
+			quiet = 1;
+			logger.json_enabled = true;
+			break;
+
 		case 'U':
 			progress_interval = atof_require(optarg, "Progress interval");
 			break;

main.hpp

@@ -5,6 +5,8 @@
 #include <atomic>
 #include <string>
 
+#include "json_logger.hpp"
+
 struct index {
 	long long start = 0;
 	long long end = 0;
@@ -38,6 +40,7 @@ void checkdisk(std::vector<struct reader> *r);
 extern int geometry_scale;
 extern int quiet;
 extern int quiet_progress;
+extern json_logger logger;
 extern double progress_interval;
 extern std::atomic<double> last_progress;
 

man/tippecanoe.1

@@ -687,6 +687,8 @@ If you don't specify, it will use \fB\fC/tmp\fR\&.
 .IP \(bu 2
 \fB\fC\-U\fR \fIseconds\fP or \fB\fC\-\-progress\-interval=\fR\fIseconds\fP: Don't report progress more often than the specified number of \fIseconds\fP\&.
 .IP \(bu 2
+\fB\fC\-u\fR or \fB\fC\-\-json\-progress\fR: like \fB\fC\-quiet\fR but logs progress as a JSON object. Use in combination with \fB\fC\-U\fR\&.
+.IP \(bu 2
 \fB\fC\-v\fR or \fB\fC\-\-version\fR: Report Tippecanoe's version number
 .RE
 .SS Filters

tile.cpp

@@ -1330,6 +1330,9 @@ serial_feature next_feature(FILE *geoms, std::atomic<long long> *geompos_in, cha
 			if (!quiet && !quiet_progress && progress_time()) {
 				fprintf(stderr, "  %3.1f%%  %d/%u/%u  \r", progress, z, tx, ty);
 			}
+			if (logger.json_enabled && progress_time()) {
+				logger.progress_tile(progress);
+			}
 			*oprogress = progress;
 		}
 
@@ -2325,6 +2328,9 @@ long long write_tile(FILE *geoms, std::atomic<long long> *geompos_in, char *meta
 			if (!quiet && !quiet_progress && progress_time()) {
 				fprintf(stderr, "  %3.1f%%  %d/%u/%u  \r", progress, z, tx, ty);
 			}
+			if (logger.json_enabled && progress_time()) {
+				logger.progress_tile(progress);
+			}
 			oprogress = progress;
 		}