MeshCache: add error handling to `fread()` calls

Handle return value of `fread()`, by showing an error message when the
file cannot be read from and stopping further processing. Not only is
error handing a good idea, it also prevents GCC from warning that the
return value of `fread()` should not be ignored.

This is similar to {D9916}.

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D10079

2 files changed, 28 insertions, 5 deletions

diff --git a/source/blender/modifiers/intern/MOD_meshcache_mdd.c b/source/blender/modifiers/intern/MOD_meshcache_mdd.c
index d216c14ab43..22e49434f7d 100644
--- a/source/blender/modifiers/intern/MOD_meshcache_mdd.c
+++ b/source/blender/modifiers/intern/MOD_meshcache_mdd.c
@@ -110,17 +110,26 @@ static bool meshcache_read_mdd_range_from_time(FILE *fp,
     return false;
   }
 
+  size_t num_frames_read = 0;
+  size_t num_frames_expect = mdd_head.frame_tot;
+  errno = 0;
   for (i = 0; i < mdd_head.frame_tot; i++) {
-    fread(&f_time, sizeof(float), 1, fp);
+    num_frames_read += fread(&f_time, sizeof(float), 1, fp);
 #ifdef __LITTLE_ENDIAN__
     BLI_endian_switch_float(&f_time);
 #endif
     if (f_time >= time) {
+      num_frames_expect = i + 1;
       break;
     }
     f_time_prev = f_time;
   }
 
+  if (num_frames_read != num_frames_expect) {
+    *err_str = errno ? strerror(errno) : "Timestamp read failed";
+    return false;
+  }
+
   if (i == mdd_head.frame_tot) {
     frame = (float)(mdd_head.frame_tot - 1);
   }
@@ -165,12 +174,14 @@ bool MOD_meshcache_read_mdd_index(FILE *fp,
     return false;
   }
 
+  size_t num_verts_read = 0;
+  errno = 0;
   if (factor >= 1.0f) {
 #if 1
     float *vco = *vertexCos;
     uint i;
     for (i = mdd_head.verts_tot; i != 0; i--, vco += 3) {
-      fread(vco, sizeof(float[3]), 1, fp);
+      num_verts_read += fread(vco, sizeof(float[3]), 1, fp);
 
 #  ifdef __LITTLE_ENDIAN__
       BLI_endian_switch_float(vco + 0);
@@ -195,7 +206,7 @@ bool MOD_meshcache_read_mdd_index(FILE *fp,
     uint i;
     for (i = mdd_head.verts_tot; i != 0; i--, vco += 3) {
       float tvec[3];
-      fread(tvec, sizeof(float[3]), 1, fp);
+      num_verts_read += fread(tvec, sizeof(float[3]), 1, fp);
 
 #ifdef __LITTLE_ENDIAN__
       BLI_endian_switch_float(tvec + 0);
@@ -209,6 +220,11 @@ bool MOD_meshcache_read_mdd_index(FILE *fp,
     }
   }
 
+  if (num_verts_read != mdd_head.verts_tot) {
+    *err_str = errno ? strerror(errno) : "Vertex coordinate read failed";
+    return false;
+  }
+
   return true;
 }
 
diff --git a/source/blender/modifiers/intern/MOD_meshcache_pc2.c b/source/blender/modifiers/intern/MOD_meshcache_pc2.c
index 0ef9f26f1d7..ea8cc334dd9 100644
--- a/source/blender/modifiers/intern/MOD_meshcache_pc2.c
+++ b/source/blender/modifiers/intern/MOD_meshcache_pc2.c
@@ -151,11 +151,13 @@ bool MOD_meshcache_read_pc2_index(FILE *fp,
     return false;
   }
 
+  size_t num_verts_read = 0;
+  errno = 0;
   if (factor >= 1.0f) {
     float *vco = *vertexCos;
     uint i;
     for (i = pc2_head.verts_tot; i != 0; i--, vco += 3) {
-      fread(vco, sizeof(float[3]), 1, fp);
+      num_verts_read += fread(vco, sizeof(float[3]), 1, fp);
 
 #ifdef __BIG_ENDIAN__
       BLI_endian_switch_float(vco + 0);
@@ -170,7 +172,7 @@ bool MOD_meshcache_read_pc2_index(FILE *fp,
     uint i;
     for (i = pc2_head.verts_tot; i != 0; i--, vco += 3) {
       float tvec[3];
-      fread(tvec, sizeof(float[3]), 1, fp);
+      num_verts_read += fread(tvec, sizeof(float[3]), 1, fp);
 
 #ifdef __BIG_ENDIAN__
       BLI_endian_switch_float(tvec + 0);
@@ -184,6 +186,11 @@ bool MOD_meshcache_read_pc2_index(FILE *fp,
     }
   }
 
+  if (num_verts_read != pc2_head.verts_tot) {
+    *err_str = errno ? strerror(errno) : "Vertex coordinate read failed";
+    return false;
+  }
+
   return true;
 }