g.proj: add JSON support

general/g.proj/Makefile

@@ -3,7 +3,7 @@ MODULE_TOPDIR = ../..
 PGM = g.proj
 
 EXTRA_INC = $(PROJINC) $(GDALCFLAGS)
-LIBES = $(GPROJLIB) $(GISLIB) $(GDALLIBS) $(PROJLIB)
+LIBES = $(GPROJLIB) $(GISLIB) $(GDALLIBS) $(PROJLIB) $(PARSONLIB)
 DEPENDENCIES = $(GPROJDEP) $(GISDEP)
 
 include $(MODULE_TOPDIR)/include/Make/Module.make

general/g.proj/local_proto.h

@@ -4,6 +4,8 @@ extern struct Key_Value *projinfo, *projunits, *projepsg;
 extern char *projsrid, *projwkt;
 extern struct Cell_head cellhd;
 
+enum OutputFormat { PLAIN, SHELL, JSON };
+
 /* input.c */
 void input_currloc(void);
 
@@ -16,12 +18,12 @@ int input_georef(char *);
 #endif
 
 /* output.c */
-void print_projinfo(int);
+void print_projinfo(enum OutputFormat);
 void print_datuminfo(void);
-void print_proj4(int);
+void print_proj4(int, enum OutputFormat);
 
 #ifdef HAVE_OGR
-void print_wkt(int, int);
+void print_wkt(int, int, enum OutputFormat);
 #endif
 
 /* datumtrans.c */

general/g.proj/main.c

@@ -28,6 +28,7 @@ struct Cell_head cellhd;
 
 int main(int argc, char *argv[])
 {
+    enum OutputFormat outputFormat;
     /* TODO: replace most of these flags with an option to select the
      * output format */
     struct Flag *printinfo, /* Print contents of PROJ_INFO & PROJ_UNITS */
@@ -53,7 +54,8 @@ int main(int argc, char *argv[])
 #endif
         *listcodes, /* list codes of given authority */
         *datum,     /* datum to add (or replace existing datum) */
-        *dtrans;    /* index to datum transform option          */
+        *dtrans,    /* index to datum transform option          */
+        *format;    /* output format */
     struct GModule *module;
 
     int formats;
@@ -223,9 +225,26 @@ int main(int argc, char *argv[])
     location->guisection = _("Create");
     location->description = _("Name of new project (location) to create");
 
+    format = G_define_standard_option(G_OPT_F_FORMAT);
+    format->options = "plain,shell,json";
+    format->descriptions = _("plain;Human readable text output;"
+                             "shell;shell script style text output;"
+                             "json;JSON (JavaScript Object Notation);");
+    format->guisection = _("Print");
+
     if (G_parser(argc, argv))
         exit(EXIT_FAILURE);
 
+    if (strcmp(format->answer, "json") == 0) {
+        outputFormat = JSON;
+    }
+    else if ((strcmp(format->answer, "shell") == 0) || shellinfo->answer) {
+        outputFormat = SHELL;
+    }
+    else {
+        outputFormat = PLAIN;
+    }
+
     /* Initialisation & Validation */
 
     /* list codes for given authority */
@@ -326,14 +345,14 @@ int main(int argc, char *argv[])
 #endif
     }
     if (printinfo->answer || shellinfo->answer)
-        print_projinfo(shellinfo->answer);
+        print_projinfo(outputFormat);
     else if (datuminfo->answer)
         print_datuminfo();
     else if (printproj4->answer)
-        print_proj4(dontprettify->answer);
+        print_proj4(dontprettify->answer, outputFormat);
 #ifdef HAVE_OGR
     else if (printwkt->answer)
-        print_wkt(esristyle->answer, dontprettify->answer);
+        print_wkt(esristyle->answer, dontprettify->answer, outputFormat);
 #endif
     else if (location->answer)
         create_location(location->answer);

general/g.proj/output.c

@@ -21,64 +21,99 @@
 #include <grass/gprojects.h>
 #include <grass/glocale.h>
 #include <grass/config.h>
+#include <grass/parson.h>
 
 #ifdef HAVE_OGR
 #include <cpl_csv.h>
 #endif
 
 #include "local_proto.h"
 
-static int check_xy(int shell);
+static int check_xy(enum OutputFormat);
+static void print_json(JSON_Value *);
 
 /* print projection information gathered from one of the possible inputs
  * in GRASS format */
-void print_projinfo(int shell)
+void print_projinfo(enum OutputFormat format)
 {
     int i;
+    JSON_Value *value;
+    JSON_Object *object;
 
-    if (check_xy(shell))
+    if (check_xy(format))
         return;
 
-    if (!shell)
+    if (format == PLAIN)
         fprintf(
             stdout,
             "-PROJ_INFO-------------------------------------------------\n");
+
+    if (format == JSON) {
+        value = json_value_init_object();
+        object = json_object(value);
+    }
+
     for (i = 0; i < projinfo->nitems; i++) {
         if (strcmp(projinfo->key[i], "init") == 0)
             continue;
-        if (shell)
+        switch (format) {
+        case PLAIN:
             fprintf(stdout, "%s=%s\n", projinfo->key[i], projinfo->value[i]);
-        else
+            break;
+        case SHELL:
             fprintf(stdout, "%-11s: %s\n", projinfo->key[i],
                     projinfo->value[i]);
+            break;
+        case JSON:
+            json_object_set_string(object, projinfo->key[i],
+                                   projinfo->value[i]);
+            break;
+        }
     }
 
     /* TODO: use projsrid instead */
     if (projsrid) {
-
-        if (!shell) {
+        switch (format) {
+        case PLAIN:
             fprintf(stdout, "-PROJ_SRID----------------------------------------"
                             "---------\n");
             fprintf(stdout, "%-11s: %s\n", "SRID", projsrid);
-        }
-        else
+            break;
+        case SHELL:
             fprintf(stdout, "%s=%s\n", "srid", projsrid);
+            break;
+        case JSON:
+            json_object_set_string(object, "srid", projsrid);
+            break;
+        }
     }
 
     if (projunits) {
-        if (!shell)
+        if (format == PLAIN)
             fprintf(stdout, "-PROJ_UNITS---------------------------------------"
                             "---------\n");
         for (i = 0; i < projunits->nitems; i++) {
-            if (shell)
-                fprintf(stdout, "%s=%s\n", projunits->key[i],
-                        projunits->value[i]);
-            else
+            switch (format) {
+            case PLAIN:
                 fprintf(stdout, "%-11s: %s\n", projunits->key[i],
                         projunits->value[i]);
+                break;
+            case SHELL:
+                fprintf(stdout, "%s=%s\n", projunits->key[i],
+                        projunits->value[i]);
+                break;
+            case JSON:
+                json_object_set_string(object, projunits->key[i],
+                                       projunits->value[i]);
+                break;
+            }
         }
     }
 
+    if (format == JSON) {
+        print_json(value);
+    }
+
     return;
 }
 
@@ -130,13 +165,16 @@ void print_datuminfo(void)
 }
 
 /* print input projection information in PROJ format */
-void print_proj4(int dontprettify)
+void print_proj4(int dontprettify, enum OutputFormat format)
 {
     struct pj_info pjinfo;
     char *i, *projstrmod;
     const char *projstr;
     const char *unfact;
 
+    JSON_Value *value;
+    JSON_Object *object;
+
     if (check_xy(FALSE))
         return;
 
@@ -187,25 +225,38 @@ void print_proj4(int dontprettify)
     if (!projstrmod)
         projstrmod = G_store(projstr);
 
-    for (i = projstrmod; *i; i++) {
-        /* Don't print the first space */
-        if (i == projstrmod && *i == ' ')
-            continue;
-
-        if (*i == ' ' && *(i + 1) == '+' && !(dontprettify))
-            fputc('\n', stdout);
-        else
-            fputc(*i, stdout);
+    switch (format) {
+    case JSON:
+        value = json_value_init_object();
+        object = json_object(value);
+        json_object_set_string(object, "proj4", projstrmod);
+        print_json(value);
+        break;
+    default:
+        for (i = projstrmod; *i; i++) {
+            /* Don't print the first space */
+            if (i == projstrmod && *i == ' ')
+                continue;
+
+            if (*i == ' ' && *(i + 1) == '+' && !(dontprettify))
+                fputc('\n', stdout);
+            else
+                fputc(*i, stdout);
+        }
+        fputc('\n', stdout);
+        break;
     }
-    fputc('\n', stdout);
+
     G_free(projstrmod);
 
     return;
 }
 
 #ifdef HAVE_OGR
-void print_wkt(int esristyle, int dontprettify)
+void print_wkt(int esristyle, int dontprettify, enum OutputFormat format)
 {
+    JSON_Value *value;
+    JSON_Object *object;
     char *outwkt;
 
     if (check_xy(FALSE))
@@ -277,7 +328,17 @@ void print_wkt(int esristyle, int dontprettify)
 #endif
 
     if (outwkt != NULL) {
-        fprintf(stdout, "%s\n", outwkt);
+        switch (format) {
+        case JSON:
+            value = json_value_init_object();
+            object = json_object(value);
+            json_object_set_string(object, "wkt", outwkt);
+            print_json(value);
+            break;
+        default:
+            fprintf(stdout, "%s\n", outwkt);
+            break;
+        }
         CPLFree(outwkt);
     }
     else
@@ -287,15 +348,38 @@ void print_wkt(int esristyle, int dontprettify)
 }
 #endif
 
-static int check_xy(int shell)
+static int check_xy(enum OutputFormat format)
 {
+    JSON_Value *value;
+    JSON_Object *object;
     if (cellhd.proj == PROJECTION_XY) {
-        if (shell)
+        switch (format) {
+        case SHELL:
             fprintf(stdout, "name=xy_location_unprojected\n");
-        else
+            break;
+        case PLAIN:
             fprintf(stdout, "XY location (unprojected)\n");
+            break;
+        case JSON:
+            value = json_value_init_object();
+            object = json_object(value);
+            json_object_set_string(object, "name", "xy_location_unprojected");
+            print_json(value);
+            break;
+        }
         return 1;
     }
     else
         return 0;
 }
+
+void print_json(JSON_Value *value)
+{
+    char *serialized_string = json_serialize_to_string_pretty(value);
+    if (serialized_string == NULL) {
+        G_fatal_error(_("Failed to initialize pretty JSON string."));
+    }
+    puts(serialized_string);
+    json_free_serialized_string(serialized_string);
+    json_value_free(value);
+}