Dive pictures: Move metadata functions into own translation unit

Move all metadata function into new core/metadata.cpp file.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

6 files changed, 142 insertions, 78 deletions

diff --git a/core/CMakeLists.txt b/core/CMakeLists.txt
index 564dfe6ac..34e12c59b 100644
--- a/core/CMakeLists.txt
+++ b/core/CMakeLists.txt
@@ -76,6 +76,7 @@ set(SUBSURFACE_CORE_LIB_SRCS
 	gettextfromc.cpp
 	# dirk ported some core functionality to c++.
 	qthelper.cpp
+	metadata.cpp
 	divecomputer.cpp
 	exif.cpp
 	subsurfacesysinfo.cpp
diff --git a/core/dive.c b/core/dive.c
index b7ce01ea4..ab033858e 100644
--- a/core/dive.c
+++ b/core/dive.c
@@ -11,6 +11,7 @@
 #include "device.h"
 #include "divelist.h"
 #include "qthelper.h"
+#include "metadata.h"
 
 /* one could argue about the best place to have this variable -
  * it's used in the UI, but it seems to make the most sense to have it
diff --git a/core/dive.h b/core/dive.h
index a1cb7fb60..62fe31917 100644
--- a/core/dive.h
+++ b/core/dive.h
@@ -433,8 +433,6 @@ extern void dive_add_picture(struct dive *d, struct picture *newpic);
 extern bool dive_remove_picture(struct dive *d, const char *filename);
 extern unsigned int dive_get_picture_count(struct dive *d);
 extern bool picture_check_valid(const char *filename, int shift_time);
-extern void picture_load_exif_data(struct picture *p);
-extern timestamp_t picture_get_timestamp(const char *filename);
 extern void dive_set_geodata_from_picture(struct dive *d, struct picture *pic);
 extern void picture_free(struct picture *picture);
 
diff --git a/core/metadata.cpp b/core/metadata.cpp
new file mode 100644
index 000000000..bf4bfcb90
--- /dev/null
+++ b/core/metadata.cpp
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "metadata.h"
+#include "exif.h"
+#include "qthelper.h"
+#include <QString>
+#include <QFile>
+#include <QDateTime>
+
+// Fetch quint16 in big endian mode from QFile and return 0 on error.
+// This is a very specialized function for parsing JPEGs, therefore we can get away with such an in-band error code.
+static inline quint16 getShortBE(QFile &f)
+{
+	unsigned char buf[2];
+	if (f.read(reinterpret_cast<char *>(buf), 2) != 2)
+		return 0;
+	return (buf[0] << 8) | buf[1];
+}
+
+static bool parseExif(QFile &f, struct metadata *metadata)
+{
+	if (getShortBE(f) != 0xffd8)
+		return false;
+	for (;;) {
+		switch (getShortBE(f)) {
+		case 0xffc0:
+		case 0xffc2:
+		case 0xffc4:
+		case 0xffd0 ... 0xffd7:
+		case 0xffdb:
+		case 0xffdd:
+		case 0xffe0:
+		case 0xffe2 ... 0xffef:
+		case 0xfffe: {
+			quint16 len = getShortBE(f);
+			if (len < 2)
+				return false;
+			f.seek(f.pos() + len - 2); // TODO: switch to QFile::skip()
+			break;
+		}
+		case 0xffe1: {
+			quint16 len = getShortBE(f);
+			if (len < 2)
+				return false;
+			len -= 2;
+			QByteArray data = f.read(len);
+			if (data.size() != len)
+				return false;
+			easyexif::EXIFInfo exif;
+			if (exif.parseFromEXIFSegment(reinterpret_cast<const unsigned char *>(data.constData()), len) != PARSE_EXIF_SUCCESS)
+				return false;
+			metadata->longitude.udeg = lrint(1000000.0 * exif.GeoLocation.Longitude);
+			metadata->latitude.udeg = lrint(1000000.0 * exif.GeoLocation.Latitude);
+			metadata->timestamp = exif.epoch();
+			return true;
+		}
+		case 0xffda:
+		case 0xffd9:
+			// We expect EXIF data before any scan data
+			return false;
+		default:
+			return false;
+		}
+	}
+}
+
+static bool parseMP4(QFile &, metadata *)
+{
+	// TODO: Implement MP4 parsing
+	return false;
+}
+
+extern "C" mediatype_t get_metadata(const char *filename_in, metadata *data)
+{
+	data->timestamp = 0;
+	data->latitude.udeg = 0;
+	data->longitude.udeg = 0;
+
+	QString filename = localFilePath(QString(filename_in));
+	QFile f(filename);
+	if (!f.open(QIODevice::ReadOnly))
+		return MEDIATYPE_IO_ERROR;
+
+	if (parseExif(f, data)) {
+		return MEDIATYPE_PICTURE;
+	} else if(parseMP4(f, data)) {
+		return MEDIATYPE_VIDEO;
+	} else {
+		// If we couldn't parse EXIF or MP4 data, use file creation date.
+		// TODO: QFileInfo::created is deprecated in newer Qt versions.
+		data->timestamp = QFileInfo(filename).created().toMSecsSinceEpoch() / 1000;
+		return MEDIATYPE_UNKNOWN;
+	}
+}
+
+extern "C" timestamp_t picture_get_timestamp(const char *filename)
+{
+	struct metadata data;
+	get_metadata(filename, &data);
+	return data.timestamp;
+}
+
+extern "C" void picture_load_exif_data(struct picture *p)
+{
+	struct metadata data;
+	if (get_metadata(p->filename, &data) == MEDIATYPE_IO_ERROR)
+		return;
+	p->longitude = data.longitude;
+	p->latitude = data.latitude;
+}
diff --git a/core/metadata.h b/core/metadata.h
new file mode 100644
index 000000000..b5af39b30
--- /dev/null
+++ b/core/metadata.h
@@ -0,0 +1,31 @@
+#ifndef METADATA_H
+#define METADATA_H
+
+#include "units.h"
+
+struct metadata {
+	timestamp_t	timestamp;
+	degrees_t	latitude;
+	degrees_t	longitude;
+};
+
+enum mediatype_t {
+	MEDIATYPE_IO_ERROR,	// Couldn't read file
+	MEDIATYPE_UNKNOWN,	// Couldn't identify file
+	MEDIATYPE_PICTURE,
+	MEDIATYPE_VIDEO,
+};
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+enum mediatype_t get_metadata(const char *filename, struct metadata *data);
+timestamp_t picture_get_timestamp(const char *filename);
+void picture_load_exif_data(struct picture *p);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // METADATA_H
diff --git a/core/qthelper.cpp b/core/qthelper.cpp
index 93c95ab5e..1cef38184 100644
--- a/core/qthelper.cpp
+++ b/core/qthelper.cpp
@@ -10,7 +10,6 @@
 #include "time.h"
 #include "gettextfromc.h"
 #include <sys/time.h>
-#include "exif.h"
 #include "prefs-macros.h"
 #include <QFile>
 #include <QRegExp>
@@ -345,72 +344,6 @@ extern "C" xsltStylesheetPtr get_stylesheet(const char *name)
 	return xslt;
 }
 
-// Fetch quint16 in big endian mode from QFile and return 0 on error.
-// This is a very specialized function for parsing JPEGs, therefore we can get away with such an in-band error code.
-static inline quint16 getShortBE(QFile &f)
-{
-	unsigned char buf[2];
-	if (f.read(reinterpret_cast<char *>(buf), 2) != 2)
-		return 0;
-	return (buf[0] << 8) | buf[1];
-}
-
-static int parseExif(const QString &filename, easyexif::EXIFInfo &exif)
-{
-	QFile f { filename };
-	if (!f.open(QIODevice::ReadOnly))
-		return PARSE_EXIF_ERROR_NO_JPEG;
-	if (getShortBE(f) != 0xffd8)
-		return PARSE_EXIF_ERROR_NO_JPEG;
-	for (;;) {
-		switch (getShortBE(f)) {
-		case 0xffc0:
-		case 0xffc2:
-		case 0xffc4:
-		case 0xffd0 ... 0xffd7:
-		case 0xffdb:
-		case 0xffdd:
-		case 0xffe0:
-		case 0xffe2 ... 0xffef:
-		case 0xfffe: {
-			quint16 len = getShortBE(f);
-			if (len < 2)
-				return PARSE_EXIF_ERROR_NO_JPEG;
-			f.seek(f.pos() + len - 2); // TODO: switch to QFile::skip()
-			break;
-		}
-		case 0xffe1: {
-			quint16 len = getShortBE(f);
-			if (len < 2)
-				return PARSE_EXIF_ERROR_NO_JPEG;
-			len -= 2;
-			QByteArray data = f.read(len);
-			if (data.size() != len)
-				return PARSE_EXIF_ERROR_NO_JPEG;
-			return exif.parseFromEXIFSegment(reinterpret_cast<const unsigned char *>(data.constData()), len);
-		}
-		case 0xffda:
-		case 0xffd9:
-			// We expect EXIF data before any scan data
-			return PARSE_EXIF_ERROR_NO_EXIF;
-		default:
-			return PARSE_EXIF_ERROR_NO_JPEG;
-		}
-	}
-}
-
-extern "C" timestamp_t picture_get_timestamp(const char *filename)
-{
-	easyexif::EXIFInfo exif;
-	if (parseExif(localFilePath(QString(filename)), exif) != PARSE_EXIF_SUCCESS) {
-		// If we couldn't parse EXIF data, use file creation date.
-		// TODO: QFileInfo::created is deprecated in newer Qt versions.
-		QDateTime created = QFileInfo(QString(filename)).created();
-		return created.toMSecsSinceEpoch() / 1000;
-	}
-	return exif.epoch();
-}
-
 extern "C" char *move_away(const char *old_path)
 {
 	if (verbose > 1)
@@ -1336,15 +1269,6 @@ extern "C" void savePictureLocal(struct picture *picture, const char *hash, cons
 	}
 }
 
-extern "C" void picture_load_exif_data(struct picture *p)
-{
-	easyexif::EXIFInfo exif;
-	if (parseExif(localFilePath(QString(p->filename)), exif) != PARSE_EXIF_SUCCESS)
-		return;
-	p->longitude.udeg = lrint(1000000.0 * exif.GeoLocation.Longitude);
-	p->latitude.udeg = lrint(1000000.0 * exif.GeoLocation.Latitude);
-}
-
 QString get_gas_string(struct gasmix gas)
 {
 	uint o2 = (get_o2(&gas) + 5) / 10, he = (get_he(&gas) + 5) / 10;